SQL Server 2005 is the forthcoming release of the Microsoft's SQL Server database. SQL Server is currently the most popular database on the Windows platform. In 2002 it had 45% of the Windows database market, compared to 27% for Oracle, and its market is growing. [Source: Gartner Report, May 2003]. In many people's eyes, the biggest advancement in SQL Server 2005 is the inclusion of the Common Language Runtime, or CLR, within the database. As a result, developers are no longer restricted to use of Transact-SQL to write stored procedures, functions and triggers. They can now create these objects using any of the .NET languages (C#, VB.NET, C++ . . . ) and compile them into .NET assemblies in the database. In theory, assemblies provide the "best of both worlds" The code can be hosted in the secure, environment of the database, delegating memory management, garbage collection and thread support to the robust database engine, while exploiting .NET's computational power, advanced data type support, and rich array of built-in classes. The book provides an in-depth tutorial on building and using assemblies. It will focus on building assemblies in C# code, but will provide the equivalent VB.NET code in the code download. Alongside this tutorial comes a detailed examination of exactly when assemblies should and should not be used. Assemblies are not a complete replacement for T-SQL stored procedures and triggers, but are enhancements, to be used at the right place at the right time. After reading this book, the reader will be able to build robust, useful and intelligent assemblies that are safe to execute and secure to the organization.