Free and Open-Source Textbooks

Here is a (partial) list of free and/or open-source textbooks. If you find one of these more helpful than another, please let me know. Also, take a peek at Rob Beezer’s selection on this page. Moreover, the American Institute of Mathematics maintains a list of approved open-source textbooks.

Calculus

Differential Equations

Discrete Mathematics

Introduction to Proof

Linear Algebra

Combinatorics

Abstract Algebra

Real Analysis