[bokumo]

The linked PDF also has an online version which is superior in many ways because it has inline executable Sage examples. It can be found at: http://abstract.pugetsound.edu/aata/

Also, this textbook is one of several open source textbooks developed using MathBook XML which allows authors to create multiple output formats such as PDF, HTML and ePub from one canonical source document written in XML. If you are interested in learning about MathBook XML you should check out: http://mathbook.pugetsound.edu/