I really like this book, and so does my trainer (in fact, I'm giving it to her for her birthday!) Strictly speaking, it's almost more of a manual than a book. As the title indicates, it contains 101 exercises for you to use in an arena with your horse. All the exercises shown are maneuvers to be done while mounted, none are in-hand work. Most work with either English or Western styles of riding, although some are slanted more one way than another. Dressage enthusiasts will recognize much of the work here, as will some of the Western specialists.
There are five main sections in the book: Gaits; Transitions; Circles; Lateral Work; and Mini-Patterns. Each exercise covers two pages, with an overhead diagram showing the pattern created in the arena, as well as a drawing showing the desired effect in the horse. Each page has a step-by-step description of how to ride the exercise, a list of benefits, cautions to consider while doing it, and occasionally, extra notes. All the illustrations are pen and ink drawings; there are no photographs.
Some of the exercises are a little the same, I will agree with a previous reviewer on that point. But all are worth working on and getting right. The format of the book encourages you to take it to the arena with you, with a spiral binding that allows the pages to lay flat. The only thing I'd like to see is to have the pages all laminated, but that surely would have increased the cost, so I'll live with it the way it is. All in all this book is well worth owning, whether you're an Dressage rider, barrel racer, or simply a riding enthusiast who wants to increase the skill set of themselves and their horse. Don't hesitate to buy it, it's well worth the price.