This book is a text for junior, senior, or first-year graduate courses traditionally titled Foundations of Geometry and/or Non- Euclidean Geometry. The first 29 chapters are for a semester or year course on the foundations of geometry. The remaining chap- ters may then be used for either a regular course or independent study courses. Another possibility, which is also especially suited for in-service teachers of high school geometry, is to survey the the fundamentals of absolute geometry (Chapters 1 -20) very quickly and begin earnest study with the theory of parallels and isometries...