Instruct: Classify Amazon reviews into positive or negative sentiment
Query: excellent reference book for those designing magnetic motors

Last year I was seeking a reference book on permanent magnetic motors. I found this book to be an excellent choice. The subject material includes magnetic materials and properties, leading into the various classes of permanent magnet materials, a good review of Maxwell's equations, which is used to lead into several useful analytical models, before closing with a review of permanent magnet devices and electromechanical devices. If the book had included problem sets at the end of each chapter, it would have ended up as an excellent graduate level textbook on the subject. As it is, the book will serve experienced technical folks well, either as a refresher on material already known, or as a method of teaching new material in all its gory detail.