I purchased this book with the intent of teaching myself trigonometry - but after three chapters, I found I couldn't slog through the stupid fantasy story the book's structured around. I mean it, it's godawful, and renders the book entirely unreadable. I'm now going through Peter Selby's _Geometry and Trigonometry for Calculus_, which is far, far more palatable and straightforward.

I have read second edition of this book.I like the early chapters of this book. It's fun and easy to understand.
But there are some major errors and the book explains some concepts in a too much incomplete inductive way.
To begin with, the standing wave formula in the chapter 9 is different from the formula on many other college physics books.
This book says it Y=Asin(kx)sin(wt). But all other college physics books say it Y=Asin(kx)cos(wt).:-<
Another example, the answer to the exercise number 47 of the chapter 10 of this book, there is only one value for the x. Actually, there are two values. And if you seleted the same way with this book to solve this problem, you have to consider another value. Not just discard the extraneous root! Since the root value have to be interpreted to a value for the cosine as well as sine, because the quadratic equation formed exactly same with the case of cosine.
Additional example is the answer to the exercise number 57 of the chapter 10. The book omits two values. This error is very related with the concepts of chapter 12.
Furthermore, the book explains some concepts in a too much incomplete inductive way. An inductive way does not guarantee a theorem is true(well, the mathematical induction is an exception) . So it must used in a careful way. But this book abuse it. For example, see the exercise number 41 of the chapter 14. The book explains(actually make reader think by solving a problem) the existance of the polar triangle by just calculate a single instance of a spherical triangle. I think it must be presented by proving cosBcosC-sinBsinCcosa equals to -cosA by applying the law of cosines for sides and the fact sinBsinC becomes bc(1-(cosA)^2)/((sina)^2).Despite of the fact it may lead to a clumsy algebric experience.
In conclusion, although you may become friendly with the trigonometry functions with this book, you are still ambiguous and skeptical about some of the trigonometric concepts.You have to create your own exercises to make sure what you've learn from this book.:-<

I think Trigonometry the Easy Way is a fairly good book. I read it, it made sense to me, and the storyline was rather interesting. It does have some problems: The exercises at the end of each chapter are much harder than what was covered in the main part of the chapter, there are relatively few examples, and the principles of trigonometry are introduced in an unclear way. An example of this is, "Will you get sick to the subject!" Recordis cried. You always go off on tangents!" "Very well," the king declared. "We will call the other ratio the tangent ratio." Overall it was pretty good book for people wanting to learn trigonometry in a fun way.