Another great Dover book of mathematics. While rigorous enough to be a textbook, the examples couldn't be more down to earth and easy to read. If you're new to this kind of math and proofs in general, it can be overwhelming so maybe take one chapter at a time. His introduction is excellent and it's interesting to realize that the algebra we learn in elementary school is just one out of about 200 algebras that mathematicians have analyzed. In it's broadest sense, an "algebra" is a set of rules applied to a set of numbers; the author handles the abstraction very well.