I purchased the Programming Guidebook with considerable hesitation; to all appearances the Guidebooks are intended for the discerning cognoscenti, whereas I am very much a Mathematica novice.
The Programming Guidebook turned out to be a pleasant surprise: while there is a vast amount of material that would benefit the expert, it is also a careful and patient instruction book for the beginner.
Mathematica is a complex system; at first acquaintance it appears to be a bewildering collection of expressions and ad hoc programming styles. This book is a pedagogical masterpiece: it brings order to this seeming chaos by revealing the underlying framework. Topics are organized into comprehensible groups and the author focuses on each in detail.
Some parts that particularly appealed to this reader:
The section in Chapter 1 on Solutions to "What you always wanted to compute". This is a wonderfully whimsical list of problems that the author has gathered over many years and each is backed up by several references. This section is an unexpected delight and following up on the references provides an education in itself. The very first paragraph in Chapter 2, where the author provides one of the keys to unraveling Mathematica. The section in Chapter 3 on lambda calculus, which clarifies the use of pure functions. The entire collection of topics in Chapter 4 on meta-Mathematica.
Chapter 5 deals with the topic that is probably most foreign to those like myself used to traditional languages, (Fortran, C, C++); the treatment in this chapter is outstanding. Chapter 6 shows how Mathematica uses lists as a unified approach for vectors, matrices and tensors. Be aware however, that the book does require a fair background in mathematics or physics, (bachelor's or above).
It is clear that this is a labor of love; the author is deeply excited by the capabilities of Mathematica, and does his best to share his enthusiasm with the reader. The result is an inspiring book that is richly deserving of high praise. To fellow novices aspiring to use Mathematica gainfully, I can recommend the Programming Guidebook without hesitation. With study and patience, this Guidebook will dramatically enhance your ability to use Mathematica successfully.
I still believe my path to skillful use of Mathematica is going to be a long one, but it does not matter - with a guide like this, I expect to enjoy the journey immensely.