Well, the book is certainly technical and not
for the faint of heart. My biggest beef with it
is that none of the code works as advertised under
X11R6 (X_CreateWindow errors). The next problem
is that the code examples are extremely difficult
to follow. You think at first that you are looking
at the progressive development of a piece of code...
Except that each new piece makes changes to the
last piece, but never draws your attention to it.
The code examples seem to be more of a work in
progress, written hastily as the book was being
written.

I must say that overall I am extremely disappointed
with the quality of this book. I am usually the first
one to recommend going out and purchasing an O'Reilly
book, but this series sucks eggs.