There are two textbooks for non-photorealistic rendering:
Neither of the textbooks is really that important for the course.
The best source of information is the papers that make up the
topics presented in lecture. Pointers to the papers will appear
on the lecture notes page.
Non-Photorealistic Computer Graphics by Strothotte
and Schlechtweg is the "official" textbook for this course
(though it's still optional). It's a well-written book.
It's also fairly thorough, to the extent that any book can
be called thorough for such an amorphous, heterogeneous
and rapidly expanding area of research.
Non-Photorealistic Rendering by Gooch and Gooch is the
other well-known book in this area. I believe there's a new
edition coming out soon.
There are also some very useful online resources:
Papers on NPR appear in most computer graphics venues, but it's
especially worthwhile looking at those published in the
Complete papers for both conferences are easily available through
the university's library website.
- Craig Reynolds has an annotated list of
in NPR, though it appears not to have been updated since
- There's an excellent online bibliography of NPR papers maintained
at the Unviersity of Magdeburg by Stefan Schlechtweg.