Like many good educational books, there's an informal narrative throughout, used judiciously to reinforce concepts or alleviate any doubts the reader may feel towards drier exercises.
The format is unlike most educational books about the guitar I've read. It was a welcome relief to see a lot more writing to explain the usefulness of exercises and how I could use them in different ways as my playing improved.
The introduction is comprehensive, outlining what can be done with the guitar and what guitarists can achieve (through practice). This is quite a few pages and covers the all the core skills in an enthusiastic but systematic fashion, providing lots of practical advice; a reference book in itself.
The topics covered (Exercises, Theorey, Scales and Chords) are well rounded, not venturing far outside the realms of what is immediately useful but making references to guitarists to research if your interests lead you in that direction.
The attention to detail regarding techniques for each exercise is the best I've read. It goes far beyond providing some tablature. At no stage did I feel I'd been left with a strange bit of atonal tablature, the meanest exercises come with a few words of solace, cajoling or a description of the benefits to your playing.
This book is distilled good guitar teacher, balancing the pursuit of technical proficiency with the pleasure of playing and interacting with music and fellow musicians.
The foreword says the book is aimed at guitarists who've got so far and hit a rut. The level of proficiency isn't rigidly determined, and I can see aspects of the book that would be rewarding to any of the guitarists I've ever met, rut or not.