Most of us like to read in the little bit of "downtime" we have -- commute to work, standing on a supermarket line, waiting for someone at a restaurant, etc. Those of us actively learning a language would like a thin and light no-nonsense book to study from. Clearly, textbooks are too clunky and heavy to stuff into a handbag. On the other hand, reference books have too much detail and not enough information. This book is the *perfect* compromise between the two.
There's a long period of time between reading information and assimilating information. The key for most of us is practice, practice, practice. This book is perfect for those of us who have read about the various Spanish verb tenses, but still need the clarification, repetition, and reinforcement that is required to master a language. The book is a reference in the sense that it contains lists and data. Yet its more than a reference in the sense that it covers the material needed to communicate in Spanish effectively without covering the exotic material that would only obscure the goal of becoming proficient at knowing and using verb tenses. Coupled with the low price, it is truly a remarkable little book that deserves space on every Spanish student's bookshelf.
Brandon Simpson's pedagogy is spot-on. He refuses to call any verb that is predictable via some kind of pattern an "irregular verb". This is the "can do" approach to learning. While most professors would call "tener" an irregular verb, Mr. Simpson explains in very simple language why it is NOT irregular. In his view, there are really not many irregular verbs, so the reader spends less energy stressing over "why are there so many irregular verbs" and more time learning.
There are tons of analogies, mnemonics, explanations, etc to help make Spanish verb tenses easier to master for the Spanish student. This book is highly recommended.