REALbasic is a very inexpensive program that allows users to design full-fledged applications. Simply put, it is like having Visual Basic on the Mac. It is an application for writing applications that are astonishingly small and fast. REALbasic uses a simple interface and an object- and event-oriented language; this makes development, maintenance, and alteration of projects very easy. There is no other program like this for the Mac. If you want to write a Mac application, you have little choice of application frameworks, and REALbasic is the only one with visual design, object orientation, and an easy language.
With the Macintosh's popularity on the rise and REALbasic, which presently only runs on Mac, with plans to make Windows applications, the interested audience is wider than the platform implies. Presently there are no ordered instructional books for REALbasic.