Cocoa is the framework that is used by Apple and third party developers in order to create software on Mac OS X. Fore example, applications like iPhoto, Pages, etc. are developed with Cocoa. Cocoa is composed of two main parts : – The first one is the Objective-C language with can be seen as C with objects (among other great functionalities). – The second one is the framework itself which contains a lot of basic classes that can be used in order to develop an applications. This framework came from NextStep, and it is the reason why all the classes begin by NS*. More information about Cocoa can be found on the Apple web site at :