OS/2 Warp Version 3 is IBM's 32-bit operating system. The application programming interfaces (APIs) allow developers and programmers to create and customize applications in OS/2. To understand this text, one must be familiar with the terms presentation manager which is OS/2's graphical-user interface, and GPI which is how programmers create graphics under OS/2. This text is structured to make programmer's/developer's job easier by organizing the functions that they use on a daily basis in the sequence of how they programme.

The API functions will be placed into logical groups with brief descriptions of each concept before each grouping. This saves the programmer from having to read both the IBM programming concepts book and the API functions reference. There will also be an appendix that lists the function calls alphabetically. The book will be cross-referenced by page number and undocumented features that are currently available only by word of mouth to be discussed. Designed and structured for how programmers actually do their jobs, this text features the more useful undocumented functions.