Apple has worked hard to integrate the same technologies used in iOS development into OS X applications. This allows developers to create applications that operate on the entire Apple ecosystem, including Mac, iPhone, iPad, and iPod. The OS X App Store is another potential revenue opportunity for developers. The recipes in this chapter will help you build OS X applications. The more platforms your application is available on, the more useful your application is to users. Much of OS X programming is similar to iOS; however, the primary framework—AppKit—is a different set of user-interface components and APIs. In addition, OS X applications frequently use multiple windows, toolbars, menus, and other desktop paradigms.