103 Trigonometry Problems: From the Training of the USA IMO Team

From the reviews:

The way chosen by the authors of this book is one that goes directly to the interested student. The theoretical facts are presnented at the beginning of each paragraph and then problems with solutions are discussed...Most of the themes are from so-called trigonometric goemetry, making the book more pleasant for the interested student. Each topic is punctured by a lot of examples. I [note] the beautiful topics on spheric trigonometry which is nowadays forgetten in schools...To conclude, I enjoyed a wonderful text in trigonometry which contains also a lot of real important mathematical ideas. I recommend it as a basic text for all students and teachers involved in high school competitions as competitors or coaches. ---Revue Roumaine de Mathematiques Pures et Appliquees

The title of this book already says everything about the content: 103 trigonometry problems that were given in the training and testing of the US International Mathematical Olympiad team are presented along with their solutions. ... The presentation is clear, accurate and extensive. For these reasons the book is very easy to read and leads the reader to astonishing insights in an elementary field of mathematics. It is therefore also very appropriate as a textbook ... . (St. Goetz, Monatshefte fur Mathematik, Vol. 149 (3), 2006)