System Overview

The Application Kit
The Device Kit
The Game Kit
The Input Server
The Interface Kit
The Kernel Kit
The Mail Kit
The Media Kit
The Midi Kit
The Network Kit
The OpenGL Kit
The Storage Kit
The Support Kit
The Translation Kit

The System Overview part of this book provides information on how the various classes within the kits (inter)operate to power the BeOS operating system

The Application Kit and the Interface Kit are the 2 most important kits to understand.