And, in fact, it's not a bad book. Overall, Walnum has done a good job, albeit with many flaws and limitations, none of them entirely fatal. It's at its least satisfactory with the base language and its keywords. The explanations are correct, though often incomplete. The concepts and techniques articles are generally models of technical prose as far as clarity and form are concerned, but again there is the question of completeness.
Articles are cross referenced to related articles rather exhaustively.
The editing and layout per se seem superb, as flawless as could reasonably be expected in a first edition. Some of my comments which follow regarding missing material are based on my best laborious effort to locate topics that just don't seem to be there, but might conceivably be covered somewhere in the volume. The articles on the mathematical operators are exceedingly lightweight from a mathematical point of view. You'll have to find out by experimentation, since such border cases aren't mentioned in this work. And so forth.