The Visual Component Library (VCL) is visual part of Delphi's object oriented class library. Delphi's class library consists of a huge number of classes descending from TObject, the root object, and the VCL generally comprises the classes that descend from TComponent. Thus VCL classes are generally termed components. It was developed by Borland for use in its Delphi and C++ Builder software development environment. It is written in Object Pascal. Much of the popularity of VCL comes from its tight integration with visual RAD tools from Borland.