Algebra: Themes, Tools, Concepts (ATTC) is an algebra textbook I co-authored with Anita Wah in the early 90's. It was ground-breaking in some ways, and includes many extraordinarily effective approaches to the teaching of algebra. In fact, ATTC features powerful lessons on many parts of secondary school math, which are used by teachers in grades 7 to 12.
On the other hand, ATTC is not particularly easy to use as a textbook, and never became a best-seller. Thus, the publisher decided to declare it out of print, and the copyright reverted to the authors. It is now available absolutely free, on my Web site, for your non-commercial use.
Thanks to Google digitization, I have been able to post searchable, full-color copies of ATTC and its Teacher's Edition, in addition to the files that have been there for a while. Check it out: