Lattice-ordered Groups: an introduction,, published by D. Reidel in 1988. This is a technical monograph providing the basics for understanding lattice-ordered groups, the topic on which I have done most of my own mathematical research. It includes a comprehensive bibliography, and a section devoted to examples.

A First Course in Abstract Algebra: Rings, Groups and Fields, published by Prindle, Weber & Schmidt in 1995. This is an examples driven undergraduate text in abstract algebra, which begins with commutative rings, rather than the more customary beginning with group theory. A new and improved second edition of this book was published in 2005 by Chapman and Hall. An errata list for this book is available on Todd Feil's Home Page.

Sherlock Holmes in Babylon, published by the Mathematical Association of America in 2004. This book is a collection of 44 articles on the history of mathematics, published in MAA journals over the past 100 years. My co-editors are Robin Wilson and Victor Katz.  Here is a recent review.