Grubb's HIKING ARIZONA is a great book for someone who wants to hike in Colorado: it's possible to hike a over a third of the trails described in this guidebook and never see the actual desert. I was not surprised to learn Grubbs published another book on N. AZ hiking specifically, given the sheer attention given to the Kaibab, Coconino, and Grand Canyon areas of the state. Furthermore, the author's promise to focus on less popular trails only rings true in these chapters, because once the guidebook hits Phoenix and the rest of the state, almost all the noted trails are incredibly popular or well known.
I noticed several errors in the text, such as trails being misnamed (AFAIK, there is no "Dog Lake" in the Kaibab Nat'l Forest, for example). However, the trails themselves seem to be accurately described, and there is a wide variety of hikes ranging from beginner to expert difficulty. The attention given to hikes on reservations, and how to hike them while being respectful to their respective tribes, is another point in the book's favor. Trivia about Arizona forestry and specific hikes is also scattered throughout the book.
HIKING ARIZONA is the definition of "just okay." It's better than relying on phone apps like All Trails, but not by much. Although I have not read it, readers are probably better off buying Grubbs' book on hiking northern Arizona, because it's clear the author is incredibly passionate about the area.