diff --git a/NTwain/TwainSource.cs b/NTwain/TwainSource.cs
new file mode 100644
index 0000000..34140f6
--- /dev/null
+++ b/NTwain/TwainSource.cs
@@ -0,0 +1,193 @@
+using NTwain.Data;
+using NTwain.Internals;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using System.Threading;
+
+namespace NTwain
+{
+    public partial class TwainSource : INotifyPropertyChanged
+    {
+        ITwainSessionInternal _session;
+
+        internal TwainSource(ITwainSessionInternal session, TWIdentity sourceId)
+        {
+            _session = session;
+            Identity = sourceId;
+        }
+
+        /// <summary>
+        /// Opens the source for capability negotiation.
+        /// </summary>
+        /// <returns></returns>
+        public ReturnCode Open()
+        {
+            var rc = ReturnCode.Failure;
+            MessageLoop.Instance.Invoke(() =>
+            {
+                Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: OpenSource.", Thread.CurrentThread.ManagedThreadId));
+
+                rc = _session.DGControl.Identity.OpenDS(this);
+            });
+            return rc;
+        }
+
+        /// <summary>
+        /// Closes the source.
+        /// </summary>
+        /// <returns></returns>
+        public ReturnCode Close()
+        {
+            var rc = ReturnCode.Failure;
+            MessageLoop.Instance.Invoke(() =>
+            {
+                Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: CloseSource.", Thread.CurrentThread.ManagedThreadId));
+
+                rc = _session.DGControl.Identity.CloseDS();
+                if (rc == ReturnCode.Success)
+                {
+                    SupportedCaps = null;
+                }
+            });
+            return rc;
+        }
+
+
+        /// <summary>
+        /// Enables the source to start transferring.
+        /// </summary>
+        /// <param name="mode">The mode.</param>
+        /// <param name="modal">if set to <c>true</c> any driver UI will display as modal.</param>
+        /// <param name="windowHandle">The window handle if modal.</param>
+        /// <returns></returns>
+        public ReturnCode StartTransfer(SourceEnableMode mode, bool modal, IntPtr windowHandle)
+        {
+            return _session.EnableSource(mode, modal, windowHandle);
+        }
+
+        /// <summary>
+        /// Gets the source status. Only call this at state 4 or higher.
+        /// </summary>
+        /// <param name="session">The session.</param>
+        /// <returns></returns>
+        public TWStatus GetStatus()
+        {
+            TWStatus stat;
+            _session.DGControl.Status.GetSource(out stat);
+            return stat;
+        }
+
+        internal TWIdentity Identity { get; private set; }
+
+        /// <summary>
+        /// Gets the source's product name.
+        /// </summary>
+        /// <value>
+        /// The name.
+        /// </value>
+        public string Name { get { return Identity.ProductName; } }
+
+        /// <summary>
+        /// Gets the source's manufacturer name.
+        /// </summary>
+        /// <value>
+        /// The manufacturer.
+        /// </value>
+        public string Manufacturer { get { return Identity.Manufacturer; } }
+
+        /// <summary>
+        /// Gets the source's product family.
+        /// </summary>
+        /// <value>
+        /// The product family.
+        /// </value>
+        public string ProductFamily { get { return Identity.ProductFamily; } }
+
+        /// <summary>
+        /// Gets the version information.
+        /// </summary>
+        /// <value>
+        /// The version.
+        /// </value>
+        public TWVersion Version { get { return Identity.Version; } }
+
+        /// <summary>
+        /// Gets the supported data group.
+        /// </summary>
+        /// <value>
+        /// The data group.
+        /// </value>
+        public DataGroups DataGroup { get { return Identity.DataGroup; } }
+
+        /// <summary>
+        /// Gets the supported TWAIN protocol major number.
+        /// </summary>
+        /// <value>
+        /// The protocol major number.
+        /// </value>
+        public int ProtocolMajor { get { return Identity.ProtocolMajor; } }
+
+        /// <summary>
+        /// Gets the supported TWAIN protocol minor number.
+        /// </summary>
+        /// <value>
+        /// The protocol minor number.
+        /// </value>
+        public int ProtocolMinor { get { return Identity.ProtocolMinor; } }
+
+
+        static readonly CapabilityId[] _emptyCapList = new CapabilityId[0];
+
+        private IList<CapabilityId> _supportedCaps;
+        /// <summary>
+        /// Gets the supported caps for this source.
+        /// </summary>
+        /// <value>
+        /// The supported caps.
+        /// </value>
+        public IList<CapabilityId> SupportedCaps
+        {
+            get
+            {
+                if (_supportedCaps == null && _session.State > 3)
+                {
+                    _supportedCaps = GetCapabilityValues(CapabilityId.CapSupportedCaps).CastToEnum<CapabilityId>(false);
+                }
+                return _supportedCaps ?? _emptyCapList;
+            }
+            private set
+            {
+                _supportedCaps = value;
+                OnPropertyChanged("SupportedCaps");
+            }
+        }
+
+        #region INotifyPropertyChanged Members
+
+        /// <summary>
+        /// Occurs when a property value changes.
+        /// </summary>
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        /// <summary>
+        /// Raises the <see cref="PropertyChanged"/> event.
+        /// </summary>
+        /// <param name="propertyName">Name of the property.</param>
+        protected void OnPropertyChanged(string propertyName)
+        {
+            try
+            {
+                var hand = PropertyChanged;
+                if (hand != null) { hand(this, new PropertyChangedEventArgs(propertyName)); }
+            }
+            catch { }
+        }
+
+        #endregion
+    }
+}