diff --git a/OpenNest.Data/NestDetails.cs b/OpenNest.Data/NestDetails.cs
new file mode 100644
index 0000000..6af06a4
--- /dev/null
+++ b/OpenNest.Data/NestDetails.cs
@@ -0,0 +1,76 @@
+using System.Linq;
+
+namespace OpenNest.Data;
+
+/// <summary>
+/// Plate and drawing rows for one saved nest, shown below the nest list in the
+/// Database-mode nest browser. The server stores only nest-level metadata, so these
+/// rows are built from the nest's downloaded archive.
+/// </summary>
+public sealed class NestDetails
+{
+    public Units Units { get; init; }
+
+    /// <summary>One row per plate, in nest order.</summary>
+    public IReadOnlyList<NestPlateDetail> Plates { get; init; } = Array.Empty<NestPlateDetail>();
+
+    /// <summary>One row per drawing (cutoffs excluded), in nest order.</summary>
+    public IReadOnlyList<NestDrawingDetail> Drawings { get; init; } = Array.Empty<NestDrawingDetail>();
+
+    public static NestDetails FromNest(Nest nest)
+    {
+        ArgumentNullException.ThrowIfNull(nest);
+
+        var plates = new List<NestPlateDetail>(nest.Plates.Count);
+        var nested = new Dictionary<Drawing, int>(ReferenceEqualityComparer.Instance);
+
+        for (var i = 0; i < nest.Plates.Count; i++)
+        {
+            var plate = nest.Plates[i];
+            var parts = plate.Parts.Where(part => !part.BaseDrawing.IsCutOff).ToList();
+            foreach (var part in parts)
+                nested[part.BaseDrawing] = nested.GetValueOrDefault(part.BaseDrawing) + plate.Quantity;
+
+            plates.Add(new NestPlateDetail(
+                Number: i + 1,
+                Duplicates: plate.Quantity,
+                Width: plate.Size.Width,
+                Length: plate.Size.Length,
+                PartCount: parts.Count,
+                DrawingCount: parts.Select(part => part.BaseDrawing).Distinct(ReferenceEqualityComparer.Instance).Count(),
+                // A zero-size plate has no meaningful utilization; report 0 rather than NaN.
+                Utilization: plate.Area() > 0 ? plate.Utilization() : 0));
+        }
+
+        var drawings = nest.Drawings
+            .Where(drawing => !drawing.IsCutOff)
+            .Select(drawing => new NestDrawingDetail(
+                Name: drawing.Name ?? "",
+                Customer: drawing.Customer ?? "",
+                Required: drawing.Quantity.Required,
+                Nested: nested.GetValueOrDefault(drawing),
+                Area: drawing.Area))
+            .ToList();
+
+        return new NestDetails { Units = nest.Units, Plates = plates, Drawings = drawings };
+    }
+}
+
+/// <param name="Number">1-based position of the plate in the nest.</param>
+/// <param name="Duplicates">How many times the plate is cut (<see cref="Plate.Quantity"/>).</param>
+/// <param name="PartCount">Parts on one copy of the plate, cutoffs excluded.</param>
+/// <param name="Utilization">Fraction of the plate area used by parts, 0 to 1.</param>
+public sealed record NestPlateDetail(
+    int Number,
+    int Duplicates,
+    double Width,
+    double Length,
+    int PartCount,
+    int DrawingCount,
+    double Utilization);
+
+/// <param name="Nested">Parts placed across all plates, counting each plate's duplicates.</param>
+public sealed record NestDrawingDetail(string Name, string Customer, int Required, int Nested, double Area)
+{
+    public int Remaining => System.Math.Max(0, Required - Nested);
+}
diff --git a/OpenNest.Data/NestDetailsSession.cs b/OpenNest.Data/NestDetailsSession.cs
new file mode 100644
index 0000000..27aed5f
--- /dev/null
+++ b/OpenNest.Data/NestDetailsSession.cs
@@ -0,0 +1,108 @@
+namespace OpenNest.Data;
+
+/// <summary>
+/// Loads the details of the nest highlighted in the Database-mode nest browser. Moving
+/// the highlight starts a new load and cancels the previous one; a superseded load's
+/// result or failure is discarded, so details never belong to a nest that is no longer
+/// highlighted. Call from one thread (the UI thread).
+/// </summary>
+public sealed class NestDetailsSession : IDisposable
+{
+    private readonly Func<Guid, CancellationToken, Task<NestDetails>> _load;
+    private CancellationTokenSource? _pending;
+    private int _generation;
+    private bool _disposed;
+
+    /// <param name="load">
+    /// Builds the details of one nest; throws when the nest cannot be read (for example
+    /// when it no longer exists on the server).
+    /// </param>
+    public NestDetailsSession(Func<Guid, CancellationToken, Task<NestDetails>> load)
+    {
+        ArgumentNullException.ThrowIfNull(load);
+        _load = load;
+    }
+
+    /// <summary>The nest of the latest load; null before the first load and after <see cref="Clear"/>.</summary>
+    public Guid? NestId { get; private set; }
+
+    /// <summary>Details of <see cref="NestId"/>; null while loading, after a failure and after <see cref="Clear"/>.</summary>
+    public NestDetails? Details { get; private set; }
+
+    /// <summary>True while the latest load is outstanding; superseded loads do not count.</summary>
+    public bool IsLoading { get; private set; }
+
+    /// <summary>
+    /// Loads one nest's details. Returns true when they were applied, false when a later
+    /// load or <see cref="Clear"/> superseded this one. A failure of the latest load
+    /// propagates; failures of superseded loads are ignored.
+    /// </summary>
+    public async Task<bool> LoadAsync(Guid id)
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+        // Supersede before cancelling: a load that completes synchronously when cancelled
+        // must already see itself as superseded. Each source is released by its own load.
+        var cancellation = Supersede();
+        var generation = _generation;
+        NestId = id;
+        IsLoading = true;
+
+        try
+        {
+            var details = await _load(id, cancellation.Token);
+            if (generation != _generation)
+                return false;
+
+            Details = details;
+            return true;
+        }
+        catch (Exception) when (generation != _generation)
+        {
+            return false;
+        }
+        finally
+        {
+            if (ReferenceEquals(_pending, cancellation))
+                _pending = null;
+            if (generation == _generation)
+                IsLoading = false;
+            cancellation.Dispose();
+        }
+    }
+
+    /// <summary>Forgets the current details and discards any load in flight (no nest highlighted).</summary>
+    public void Clear()
+    {
+        if (_disposed)
+            return;
+
+        _generation++;
+        var pending = _pending;
+        _pending = null;
+        NestId = null;
+        Details = null;
+        IsLoading = false;
+        pending?.Cancel();
+    }
+
+    private CancellationTokenSource Supersede()
+    {
+        var previous = _pending;
+        var cancellation = new CancellationTokenSource();
+        _pending = cancellation;
+        _generation++;
+        Details = null;
+        previous?.Cancel();
+        return cancellation;
+    }
+
+    /// <summary>Cancels any load in flight (which releases its own source when it ends).</summary>
+    public void Dispose()
+    {
+        if (_disposed)
+            return;
+
+        Clear();
+        _disposed = true;
+    }
+}
diff --git a/OpenNest.Tests/Data/NestDetailsSessionTests.cs b/OpenNest.Tests/Data/NestDetailsSessionTests.cs
new file mode 100644
index 0000000..4c6c51c
--- /dev/null
+++ b/OpenNest.Tests/Data/NestDetailsSessionTests.cs
@@ -0,0 +1,165 @@
+using OpenNest.Data;
+
+namespace OpenNest.Tests.Data;
+
+public class NestDetailsSessionTests
+{
+    [Fact]
+    public async Task Load_AppliesTheNestsDetails()
+    {
+        var id = Guid.NewGuid();
+        var expected = new NestDetails();
+        var requested = new List<Guid>();
+        using var session = new NestDetailsSession((nestId, _) =>
+        {
+            requested.Add(nestId);
+            return Task.FromResult(expected);
+        });
+
+        Assert.True(await session.LoadAsync(id));
+
+        Assert.Equal(new[] { id }, requested);
+        Assert.Equal(id, session.NestId);
+        Assert.Same(expected, session.Details);
+        Assert.False(session.IsLoading);
+    }
+
+    [Fact]
+    public async Task OlderResponse_ArrivingLast_NeverReplacesTheNewerNestsDetails()
+    {
+        var loads = new ControlledLoads();
+        using var session = new NestDetailsSession(loads.Load);
+        var first = Guid.NewGuid();
+        var second = Guid.NewGuid();
+
+        var firstLoad = session.LoadAsync(first);
+        var secondLoad = session.LoadAsync(second);
+        Assert.True(loads.Tokens[0].IsCancellationRequested);
+
+        var secondDetails = new NestDetails();
+        loads.Results[1].SetResult(secondDetails);
+        Assert.True(await secondLoad);
+        loads.Results[0].SetResult(new NestDetails());
+        Assert.False(await firstLoad);
+
+        Assert.Equal(second, session.NestId);
+        Assert.Same(secondDetails, session.Details);
+    }
+
+    [Fact]
+    public async Task SupersededFailure_IsIgnored_LatestFailure_ClearsTheDetailsAndPropagates()
+    {
+        var loads = new ControlledLoads();
+        using var session = new NestDetailsSession(loads.Load);
+
+        var applied = session.LoadAsync(Guid.NewGuid());
+        loads.Results[0].SetResult(new NestDetails());
+        await applied;
+
+        var superseded = session.LoadAsync(Guid.NewGuid());
+        var latest = session.LoadAsync(Guid.NewGuid());
+        Assert.Null(session.Details);
+
+        loads.Results[1].SetException(new InvalidOperationException("old"));
+        Assert.False(await superseded);
+        Assert.True(session.IsLoading);
+
+        loads.Results[2].SetException(new InvalidOperationException("This nest no longer exists on the server."));
+        var error = await Assert.ThrowsAsync<InvalidOperationException>(() => latest);
+        Assert.Contains("no longer exists", error.Message);
+        Assert.Null(session.Details);
+        Assert.False(session.IsLoading);
+    }
+
+    [Fact]
+    public async Task SupersededLoad_CompletingSynchronouslyOnCancellation_IsNotReportedAsTheLatestFailure()
+    {
+        var calls = 0;
+        var latestDetails = new NestDetails();
+        using var session = new NestDetailsSession((_, token) =>
+        {
+            if (++calls > 1)
+                return Task.FromResult(latestDetails);
+
+            var cancelled = new TaskCompletionSource<NestDetails>();
+            token.Register(() => cancelled.SetCanceled(token));
+            return cancelled.Task;
+        });
+
+        var superseded = session.LoadAsync(Guid.NewGuid());
+        var latest = session.LoadAsync(Guid.NewGuid());
+
+        Assert.False(await superseded);
+        Assert.True(await latest);
+        Assert.Same(latestDetails, session.Details);
+        Assert.False(session.IsLoading);
+    }
+
+    [Fact]
+    public async Task IsLoading_FollowsOnlyTheLatestLoad()
+    {
+        var loads = new ControlledLoads();
+        using var session = new NestDetailsSession(loads.Load);
+
+        var first = session.LoadAsync(Guid.NewGuid());
+        var second = session.LoadAsync(Guid.NewGuid());
+        loads.Results[1].SetResult(new NestDetails());
+        await second;
+        Assert.False(session.IsLoading);
+
+        // The superseded load is still outstanding but no longer counts.
+        Assert.False(first.IsCompleted);
+        loads.Results[0].SetResult(new NestDetails());
+        Assert.False(await first);
+        Assert.False(session.IsLoading);
+    }
+
+    [Fact]
+    public async Task Clear_DiscardsTheLoadInFlightAndForgetsTheNest()
+    {
+        var loads = new ControlledLoads();
+        using var session = new NestDetailsSession(loads.Load);
+
+        var load = session.LoadAsync(Guid.NewGuid());
+        session.Clear();
+
+        Assert.True(loads.Tokens[0].IsCancellationRequested);
+        Assert.False(session.IsLoading);
+        Assert.Null(session.NestId);
+        loads.Results[0].SetResult(new NestDetails());
+        Assert.False(await load);
+        Assert.Null(session.Details);
+    }
+
+    [Fact]
+    public async Task Dispose_CancelsTheLoadAndDiscardsItsLateResponse()
+    {
+        var loads = new ControlledLoads();
+        var session = new NestDetailsSession(loads.Load);
+
+        var load = session.LoadAsync(Guid.NewGuid());
+        session.Dispose();
+
+        Assert.True(loads.Tokens[0].IsCancellationRequested);
+        loads.Results[0].SetResult(new NestDetails());
+        Assert.False(await load);
+        Assert.Null(session.Details);
+        await Assert.ThrowsAsync<ObjectDisposedException>(() => session.LoadAsync(Guid.NewGuid()));
+    }
+
+    /// <summary>Each load waits for its own result, which the test completes explicitly.</summary>
+    private sealed class ControlledLoads
+    {
+        public List<TaskCompletionSource<NestDetails>> Results { get; } = new();
+
+        public List<CancellationToken> Tokens { get; } = new();
+
+        public Task<NestDetails> Load(Guid id, CancellationToken token)
+        {
+            var result = new TaskCompletionSource<NestDetails>(TaskCreationOptions.RunContinuationsAsynchronously);
+            Results.Add(result);
+            Tokens.Add(token);
+            return result.Task;
+        }
+    }
+}
diff --git a/OpenNest.Tests/Data/NestDetailsTests.cs b/OpenNest.Tests/Data/NestDetailsTests.cs
new file mode 100644
index 0000000..1a27559
--- /dev/null
+++ b/OpenNest.Tests/Data/NestDetailsTests.cs
@@ -0,0 +1,179 @@
+using OpenNest.CNC;
+using OpenNest.Data;
+using OpenNest.Geometry;
+
+namespace OpenNest.Tests.Data;
+
+public class NestDetailsTests
+{
+    [Fact]
+    public void FromNest_ListsEachPlateWithItsDuplicatesSizePartsAndUtilization()
+    {
+        var nest = new Nest("Job") { Units = Units.Millimeters };
+        var bracket = Rectangle("Bracket", 10, 10);
+        var gusset = Rectangle("Gusset", 20, 5);
+        nest.Drawings.Add(bracket);
+        nest.Drawings.Add(gusset);
+
+        var first = nest.CreatePlate();
+        first.Size = new Size(48, 120);
+        first.Quantity = 2;
+        first.Parts.Add(new Part(bracket));
+        first.Parts.Add(new Part(bracket));
+        first.Parts.Add(new Part(gusset));
+        var cutoff = new CutOff(new Vector(30, 0), CutOffAxis.Vertical);
+        first.CutOffs.Add(cutoff);
+        first.Parts.Add(new Part(cutoff.Drawing));
+
+        var second = nest.CreatePlate();
+        second.Size = new Size(60, 60);
+        second.Quantity = 1;
+
+        var details = NestDetails.FromNest(nest);
+
+        Assert.Equal(Units.Millimeters, details.Units);
+        Assert.Collection(
+            details.Plates,
+            plate =>
+            {
+                Assert.Equal(1, plate.Number);
+                Assert.Equal(2, plate.Duplicates);
+                Assert.Equal(48, plate.Width);
+                Assert.Equal(120, plate.Length);
+                Assert.Equal(3, plate.PartCount);
+                Assert.Equal(2, plate.DrawingCount);
+                Assert.Equal((100 + 100 + 100) / (48.0 * 120), plate.Utilization, 12);
+            },
+            plate =>
+            {
+                Assert.Equal(2, plate.Number);
+                Assert.Equal(1, plate.Duplicates);
+                Assert.Equal(0, plate.PartCount);
+                Assert.Equal(0, plate.DrawingCount);
+                Assert.Equal(0, plate.Utilization);
+            });
+    }
+
+    [Fact]
+    public void FromNest_CountsNestedDrawingsAcrossPlateDuplicates_AndSkipsCutoffs()
+    {
+        var nest = new Nest("Job");
+        var bracket = Rectangle("Bracket", 10, 10);
+        bracket.Customer = "Acme";
+        bracket.Quantity.Required = 10;
+        var gusset = Rectangle("Gusset", 20, 5);
+        gusset.Quantity.Required = 1;
+        var unplaced = Rectangle("Spare", 4, 4);
+        unplaced.Quantity.Required = 3;
+        nest.Drawings.Add(bracket);
+        nest.Drawings.Add(gusset);
+        nest.Drawings.Add(unplaced);
+
+        var first = nest.CreatePlate();
+        first.Quantity = 3;
+        first.Parts.Add(new Part(bracket));
+        first.Parts.Add(new Part(bracket));
+        var second = nest.CreatePlate();
+        second.Quantity = 1;
+        second.Parts.Add(new Part(bracket));
+        second.Parts.Add(new Part(gusset));
+        second.Parts.Add(new Part(gusset));
+        var cutoff = new CutOff(new Vector(5, 0), CutOffAxis.Vertical);
+        second.CutOffs.Add(cutoff);
+        second.Parts.Add(new Part(cutoff.Drawing));
+
+        var details = NestDetails.FromNest(nest);
+
+        Assert.Collection(
+            details.Drawings,
+            drawing =>
+            {
+                Assert.Equal("Bracket", drawing.Name);
+                Assert.Equal("Acme", drawing.Customer);
+                Assert.Equal(10, drawing.Required);
+                Assert.Equal(2 * 3 + 1, drawing.Nested);
+                Assert.Equal(3, drawing.Remaining);
+                Assert.Equal(100, drawing.Area, 9);
+            },
+            drawing =>
+            {
+                Assert.Equal("Gusset", drawing.Name);
+                Assert.Equal(2, drawing.Nested);
+                Assert.Equal(0, drawing.Remaining);
+            },
+            drawing =>
+            {
+                Assert.Equal("Spare", drawing.Name);
+                Assert.Equal(0, drawing.Nested);
+                Assert.Equal(3, drawing.Remaining);
+            });
+    }
+
+    [Fact]
+    public void FromNest_ZeroSizePlate_ReportsZeroUtilizationInsteadOfNaN()
+    {
+        var nest = new Nest("Job");
+        var bracket = Rectangle("Bracket", 10, 10);
+        nest.Drawings.Add(bracket);
+        var plate = nest.CreatePlate();
+        plate.Size = new Size(0, 0);
+        plate.Parts.Add(new Part(bracket));
+
+        var detail = Assert.Single(NestDetails.FromNest(nest).Plates);
+
+        Assert.Equal(0, detail.Utilization);
+        Assert.Equal(1, detail.PartCount);
+    }
+
+    [Fact]
+    public void FromNest_OfAReadBackArchive_KeepsDuplicatesRequiredQuantitiesAndUnits()
+    {
+        // The nest browser builds details from the downloaded .nest archive, not a live nest.
+        var nest = new Nest("Job") { Units = Units.Millimeters };
+        var bracket = Rectangle("Bracket", 10, 10);
+        bracket.Quantity.Required = 8;
+        nest.Drawings.Add(bracket);
+        var plate = nest.CreatePlate();
+        plate.Size = new Size(1500, 3000);
+        plate.Quantity = 4;
+        plate.Parts.Add(new Part(bracket));
+        plate.Parts.Add(new Part(bracket, new Vector(20, 0)));
+
+        using var stream = new MemoryStream();
+        new OpenNest.IO.NestWriter(nest).Write(stream);
+        stream.Position = 0;
+        var details = NestDetails.FromNest(new OpenNest.IO.NestReader(stream).Read());
+
+        Assert.Equal(Units.Millimeters, details.Units);
+        var plateDetail = Assert.Single(details.Plates);
+        Assert.Equal(4, plateDetail.Duplicates);
+        Assert.Equal(2, plateDetail.PartCount);
+        Assert.Equal(1500, plateDetail.Width);
+        Assert.Equal(3000, plateDetail.Length);
+        var drawing = Assert.Single(details.Drawings);
+        Assert.Equal("Bracket", drawing.Name);
+        Assert.Equal(8, drawing.Required);
+        Assert.Equal(8, drawing.Nested);
+        Assert.Equal(0, drawing.Remaining);
+    }
+
+    [Fact]
+    public void FromNest_EmptyNest_HasNoRows()
+    {
+        var details = NestDetails.FromNest(new Nest("Empty"));
+
+        Assert.Empty(details.Plates);
+        Assert.Empty(details.Drawings);
+    }
+
+    private static Drawing Rectangle(string name, double width, double height)
+    {
+        var program = new OpenNest.CNC.Program();
+        program.Codes.Add(new RapidMove(new Vector(0, 0)));
+        program.Codes.Add(new LinearMove(new Vector(width, 0)));
+        program.Codes.Add(new LinearMove(new Vector(width, height)));
+        program.Codes.Add(new LinearMove(new Vector(0, height)));
+        program.Codes.Add(new LinearMove(new Vector(0, 0)));
+        return new Drawing(name, program);
+    }
+}