The Base Class Library (BCL), provides a ton of code that you as a developer can leverage to build your applications. The BCL is extensive in terms of the number of classes it provides, and an exhaustive coverage of all that it offers would require a tome all to itself. It is interesting to note that the BCL was developed almost entirely in C#. Table 2.2 provides a basic listing of the FCL namespaces and a partial listing of what can be found under that namespace.
Table 2.2 does not give a complete namespace listing, but instead lists some of the most commonly used namespaces.