It really irritates me when people who have earned degrees write bad science. This is the second book of M K-W's I've read and she just doesn't understand operant conditioning at all, or if I am really kind I might say she describes it badly.
There are some very interesting and worthwhile sections in this book, but please skip over the chapter on learning and conditioning because the descriptions of negative and postive reinforcement and particularly how it applies to riding aids are either downright wrong or so very badly worded that it would give the uninformed reader the entirely wrong impression. The author also has a habit of blurring opinion and scientific research indescriminitely, which will be annoying to anyone else of a scientific or diagnostic mindset. It's also mildly amusing to find that throughout the text she refers to her own research papers as if she were a third party.
On the up side, the book is very readable and there are many references to research performed over the years and some very interesting theories and opinions. For first time property owners there is a nice chapter on property management for horses. None of the information is startling, new or different from many other texts (except that Ms Kiley prefers to use horses to perform many tasks that others might use mechanical devices for)but it is practical and describes the issues facing horse property owners well.
I think this book is probably most of interest to horse breeders and those who are interested in foal rearing and associated topics as there is a great deal of the book dedicated to breeding, mare and stallion behaviour and foal rearing.
I'd certainly recommend this as worth a read with the reservations mentioned already.