In all his books, advanced and elementary, Dickson is noted for the extraordinary clarity of his writing. This very elementary book is no exception. From the Preface: 'This book introduces at an early stage concrete applications...We thereby obtain an abundance of simple problems whose importance is so convincing that they cannot fail to arouse real interest. Actual experience with classes has firmly convinced the author that these practical applications offer the best means to drive home the principles of trigonometry and to make the subject truly vital'.