Though elementary in nature, this book deals with fundamental issues in mathematics - number, algebra, geometry (both Euclidean and non-Euclidean) and topology. These subjects, on an advanced level, are the same ones with which much of current mathematical research is concerned and were themselves research topics of earlier periods. The material is very suitable both for advanced high school students and for college students interested in elementary mathematics from a higher standpoint. It will also be very useful to high school teachers seeking an overview of their subject matter. Contents: What is a Number?: The Positive Integers; The Integers; The Rational Numbers; The Real Numbers; The Integers Revisited; The Complex Numbers; Polynomials and Other Analogues of the Integers; The Algebra on a Dial; Groups, Finite Fields and Linear Algebra: Introduction to Groups and Their Actions; Applications to Finite Fields and the Theory of Numbers; Linear Algebra; Two- and Three-Dimensional Geometry and Topology: The Euclidean Case; Elliptic and Hyperbolic Geometry; Some Two- and Three-Dimensional Topology. Readership: High school and college teachers and students; college pre-calculus teachers and students; general readers with an interest in mathematics but a limited background.