This book is an introduction and a technical description of the Microsoft .NET technology. It covers the language C# as well as the major parts of the Microsoft .NET framework, namely the Common Language Runtime (CLR), the .NET class library, ADO.NET (ActiveX Data Objects), ASP.NET (Active Server Pages), and XML Web Services, as well as the most important tools under .NET. The book has a technical perspective and is written for programmers. It explains the general concepts of the .NET architecture and shows how to develop non-trivial applications in C#. In particular, it deals with the development of dynamic Web pages using ASP.NET, database applications using ADO.NET, as well as Web services using SOAP (Simple Object Access Protocol), WSDL (Web Service Description Language) and UDDI (Universal Description, Discovery and Integration). It is not intended as a complete reference manual since details can be found more easily using the online documentation of the .NET SDK.