The overview section is a walkthrough of many of ClanLib's components, classes and interfaces. It is highly adviceable to read it from the one end to the other, if you want to get a proper overview of what ClanLib can do for you.
The ClanLib game SDK is a library that can ease your game development in many ways. ClanLib has APIs for 2D graphics, 3D graphics, sound, network, I/O, input, GUI and resource administration. ClanLib reads a number of common image formats, either natively or through third-party libraries supported by ClanLib. ClanLib provides transparent support for OpenGL, so that you can use native OpenGL commands while letting ClanLib handle the boring parts such as window management, sound, networking and all the other things that are required to make a good game besides 3D graphics.
We will assume you're familiar with C++, and basic game programming terminology. If you're just starting out on making games, perhaps you should first look at a few of the numerous sites that describe game programming in general.
If there is something you think is missing out in the documentation, please add a comment to the page most relevant to the information you are seeking. We will then when reviewing the documentation update it based on user requests.