This website can serve as an instructor's free e-textbook/guide for teaching Calculus III as well as a student's free etextbook. The author has organized his online notes for his Calculus III course that he teach here at Lamar University. Despite the fact that these are his “class notes”, they should be accessible to anyone wanting to learn Calculus III or needing a refresher in some of the topics from the class.
These notes do assume that the reader has a good working knowledge of Calculus I topics including limits, derivatives and integration. It also assumes that the reader has a good knowledge of several Calculus II topics including some integration techniques, parametric equations, vectors, and knowledge of three dimensional space."