High Quality Content by WIKIPEDIA articles! The Base Class Library (BCL) is a standard library available to all languages using the .NET Framework. .NET includes the BCL in order to encapsulate a large number of common functions, such as file reading and writing, graphic rendering, database interaction, and XML document manipulation, which makes the programmer`s job easier. It is much larger in scope than standard libraries for most other languages, including C++, and is comparable in scope to the standard libraries of Java. The BCL is sometimes incorrectly referred to as the Framework Class Library (FCL), which is a superset including the Microsoft.* namespaces.