Algebra: Sets, Symbols, and the Language of Thought (History of Mathematics) by John Tabak
A good history of algebra that would be an ideal text for a high school math class. The book begins with the Mesopotamians, before progressing through the mathematical works of ancient Greece, India, the Islamic World and Asia. The bulk of the book, however, focuses on the works of Europeans, from Descartes and Galois to modern ideas in linear algebra.
