Index: Core/Common/src/Core.Common.Base/IObservable.cs
===================================================================
diff -u -r2a90c0c1be6114f72af65c42f0a6f334b30e4755 -re823dc6f52bf6a01f421c69b95a07e6258ec33de
--- Core/Common/src/Core.Common.Base/IObservable.cs	(.../IObservable.cs)	(revision 2a90c0c1be6114f72af65c42f0a6f334b30e4755)
+++ Core/Common/src/Core.Common.Base/IObservable.cs	(.../IObservable.cs)	(revision e823dc6f52bf6a01f421c69b95a07e6258ec33de)
@@ -1,27 +1,26 @@
 namespace Core.Common.Base
 {
     /// <summary>
-    /// This interface describes the methods that need to be implemented on a class of objects that are supposed to be observable.
-    /// Being observable let classes notify observers that they have performed an action (for example changed data).
+    /// Interface that describes the methods that need to be implemented on classes that are supposed to be observable.
+    /// Observables should (asynchronously) notify their observers of the fact that their internal state has changed.
+    /// <seealso cref="IObserver"/>
     /// </summary>
     public interface IObservable
     {
         /// <summary>
-        /// Attach an <see cref="IObserver"/> to this <see cref="IObservable"/>. Changes in the <see cref="IObservable"/> will notify the
-        /// <paramref name="observer"/>.
+        /// This method attaches <paramref name="observer"/>. As a result, changes in the <see cref="IObservable"/> will now be notified to <paramref name="observer"/>.
         /// </summary>
         /// <param name="observer">The <see cref="IObserver"/> to notify on changes.</param>
         void Attach(IObserver observer);
 
         /// <summary>
-        /// Detach an <see cref="IObserver"/> from this <see cref="IObservable"/>. Changes in the <see cref="IObservable"/> will no longer
-        /// notify the <paramref name="observer"/>.
+        /// This method dettaches <paramref name="observer"/>. As a result, changes in the <see cref="IObservable"/> will no longer be notified to <paramref name="observer"/>.
         /// </summary>
         /// <param name="observer">The <see cref="IObserver"/> to no longer notify on changes.</param>
         void Detach(IObserver observer);
 
         /// <summary>
-        /// Notifies all the observers that have been currently attached to this <see cref="IObservable"/>.
+        /// This method notifies all observers that have been currently attached to the <see cref="IObservable"/>.
         /// </summary>
         void NotifyObservers();
     }
Index: Core/Common/src/Core.Common.Base/IObserver.cs
===================================================================
diff -u -r2a90c0c1be6114f72af65c42f0a6f334b30e4755 -re823dc6f52bf6a01f421c69b95a07e6258ec33de
--- Core/Common/src/Core.Common.Base/IObserver.cs	(.../IObserver.cs)	(revision 2a90c0c1be6114f72af65c42f0a6f334b30e4755)
+++ Core/Common/src/Core.Common.Base/IObserver.cs	(.../IObserver.cs)	(revision e823dc6f52bf6a01f421c69b95a07e6258ec33de)
@@ -1,7 +1,14 @@
 namespace Core.Common.Base
 {
+    /// <summary>
+    /// Interface that describes the methods that need to be implemented on classes that are supposed to be observer.
+    /// <seealso cref="IObservable"/>
+    /// </summary>
     public interface IObserver
     {
+        /// <summary>
+        /// This method performs an update of the <seealso cref="IObserver"/>, triggered by a notification of an <seealso cref="IObservable"/>.
+        /// </summary>
         void UpdateObserver();
     }
 }
\ No newline at end of file
Index: Core/Common/src/Core.Common.Base/Observable.cs
===================================================================
diff -u -r94ef875f26bff005b1d53880c92f350b373a31ec -re823dc6f52bf6a01f421c69b95a07e6258ec33de
--- Core/Common/src/Core.Common.Base/Observable.cs	(.../Observable.cs)	(revision 94ef875f26bff005b1d53880c92f350b373a31ec)
+++ Core/Common/src/Core.Common.Base/Observable.cs	(.../Observable.cs)	(revision e823dc6f52bf6a01f421c69b95a07e6258ec33de)
@@ -4,36 +4,22 @@
 namespace Core.Common.Base
 {
     /// <summary>
-    /// Own implementation of the Observable pattern that cooperates with Observers (own IObserver interface).
-    /// In places where multiple inheritance is not possible, use IObservable instead.
+    /// Class that implements the <see cref="IObservable"/> pattern.
     /// </summary>
     public abstract class Observable : IObservable
     {
         private readonly IList<IObserver> observers = new List<IObserver>();
 
-        /// <summary>
-        /// Attach an <see cref="IObserver"/> to this <see cref="IObservable"/>. Changes in the <see cref="IObservable"/> will notify the
-        /// <paramref name="observer"/>.
-        /// </summary>
-        /// <param name="observer">The <see cref="IObserver"/> to notify on changes.</param>
         public void Attach(IObserver observer)
         {
             observers.Add(observer);
         }
 
-        /// <summary>
-        /// Detach an <see cref="IObserver"/> from this <see cref="IObservable"/>. Changes in the <see cref="IObservable"/> will no longer
-        /// notify the <paramref name="observer"/>.
-        /// </summary>
-        /// <param name="observer">The <see cref="IObserver"/> to no longer notify on changes.</param>
         public void Detach(IObserver observer)
         {
             observers.Remove(observer);
         }
 
-        /// <summary>
-        /// Notifies all the observers that have been currently attached to this <see cref="IObservable"/>.
-        /// </summary>
         public void NotifyObservers()
         {
             // Iterate through a copy of the list of observers; an update of one observer might result in detaching another observer (which will result in a "list modified" exception over here otherwise)
Index: Core/Common/src/Core.Common.Base/ObservableList.cs
===================================================================
diff -u -r7bcd564343094615f52e49178f27f7bfe22cebc8 -re823dc6f52bf6a01f421c69b95a07e6258ec33de
--- Core/Common/src/Core.Common.Base/ObservableList.cs	(.../ObservableList.cs)	(revision 7bcd564343094615f52e49178f27f7bfe22cebc8)
+++ Core/Common/src/Core.Common.Base/ObservableList.cs	(.../ObservableList.cs)	(revision e823dc6f52bf6a01f421c69b95a07e6258ec33de)
@@ -4,7 +4,7 @@
 namespace Core.Common.Base
 {
     /// <summary>
-    /// Extends the <see cref="List{T}"/> class with implementation for <see cref="IObservable"/>.
+    /// Class that extends the <see cref="List{T}"/> class with an implementation of <see cref="IObservable"/>.
     /// </summary>
     /// <typeparam name="T">The type of elements in the list.</typeparam>
     public class ObservableList<T> : List<T>, IObservable
Index: Core/Common/src/Core.Common.Base/Service/FileImportActivity.cs
===================================================================
diff -u -r358f5af627a563dd5b6903b94ba6abb16df8084e -re823dc6f52bf6a01f421c69b95a07e6258ec33de
--- Core/Common/src/Core.Common.Base/Service/FileImportActivity.cs	(.../FileImportActivity.cs)	(revision 358f5af627a563dd5b6903b94ba6abb16df8084e)
+++ Core/Common/src/Core.Common.Base/Service/FileImportActivity.cs	(.../FileImportActivity.cs)	(revision e823dc6f52bf6a01f421c69b95a07e6258ec33de)
@@ -1,20 +1,31 @@
 using System;
+using System.Linq;
 using Core.Common.Base.IO;
 using Core.Common.Base.Properties;
 
 namespace Core.Common.Base.Service
 {
+    /// <summary>
+    /// <see cref="Activity"/> for importing the data in one or more files (in the same thread).
+    /// </summary>
     public class FileImportActivity : Activity
     {
         private readonly object target;
+        private readonly string[] filePaths;
         private readonly IFileImporter importer;
-        private readonly string[] files;
+
         private bool shouldCancel;
 
         /// <summary>
-        /// One Activity (thread) for a serial file import.
+        /// Constructs a new <see cref="FileImportActivity"/>.
         /// </summary>
-        public FileImportActivity(IFileImporter importer, object target, string[] files)
+        /// <param name="importer">The <see cref="IFileImporter"/> to use for importing the data.</param>
+        /// <param name="target">The target object to import the data to.</param>
+        /// <param name="filePaths">The paths of the files to import the data from.</param>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="importer"/> is <c>null</c>.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="target"/> is <c>null</c>.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="filePaths"/> is <c>null</c> or contains no file paths.</exception>
+        public FileImportActivity(IFileImporter importer, object target, string[] filePaths)
         {
             if (importer == null)
             {
@@ -26,14 +37,14 @@
                 throw new ArgumentException("target");
             }
 
-            if (files == null)
+            if (filePaths == null || !filePaths.Any())
             {
                 throw new ArgumentException("files");
             }
 
             this.importer = importer;
             this.target = target;
-            this.files = files;
+            this.filePaths = filePaths;
         }
 
         public override string Name
@@ -46,7 +57,7 @@
 
         protected override void OnRun()
         {
-            foreach (var fileName in files)
+            foreach (var fileName in filePaths)
             {
                 ImportFromFile(fileName);