A review from The American Mathematical Monthly, Volume 16, 1909: The subject of Trigonometry as presented in this book is in accordance with the latest and most approved methods. Trigonometric Functions are defined as ratios, first for angles less than a right angle and then extended to angles in general. A valuable feature of the book is the fact that the degree of accuracy which may be expected in a result found by the aid of the tables is clearly indicated. In the treatment of oblique spherical triangles the author makes use of the Principle of Duality, whereby nearly half of the work usually required in deriving the standard formulae is saved and the usual six cases are reduced to three. A large number of illustrative problems are worked out under each topic and a large number of well graded exercises are given. The typography and mechanical execution of the book are very beautiful and artistic.