gl Guide or Guitar? grumble in good-humored.

All people recommend opengl guide, all appreciates this open language, Have read its formidable thick 7th version, from begin to end, what has it written?
Dot, from dot to dot, hardly find a function, math function like x+y=k to draw a line etc… the glsl is also put at the last chapter. simply read a bios of a computer. and yet not understand when is cpu, when is gpu is serving in a codes.

A model data was suggested to get from 3dmax or maya, then, we may finish all by them, why do we use this language?
lack illustration as well.
which book are you reading?