Although it arose from purely theoretical considerations of the
underlying axioms of geometry, the work of Einstein and Dirac has
demonstrated that hyperbolic geometry is a fundamental aspect of modern
physics. In this book, the rich geometry of the hyperbolic plane is
studied in detail, leading to the focal point of the book, Poincare's
polygon theorem and the relationship between hyperbolic geometries and
discrete groups of isometries. Hyperbolic 3-space is also discussed, and
the directions that current research in this field is taking are
sketched. This will be an excellent introduction to hyperbolic geometry
for students new to the subject, and for experts in other fields.