Geared toward students preparing to teach high school mathematics, this text is also of value to professionals, as well as to students seeking further background in geometry. It explores the principles of Euclidean and non-Euclidean geometry, and it instructs readers in both generalities and specifics of the axiomatic method. Well-written and accessible, the text begins by acquainting students with the axiomatic method as well as a general pattern of thought. Subsequent chapters present in-depth coverage of Euclidean geometry, including the geometry of four dimensions, plane hyperbolic geometry, and a Euclidean model of the hyperbolic plane. Detailed definitions, corollaries, theorems, and postulates are explained incrementally and illustrated by numerous figures. Each chapter concludes with multiple exercises that test and reinforce students' understanding of the material.