The first version of this e-book went online in 1996, at the very early stages of worldwide web content. From that start, many people have commented on and contributed to improve it and make possible this new edition. We acknowledge, with thanks, the contribution of students who worked on editing and creating figures and images for the ebook: Nathalie Hua, Stephanie Tera, Jessica Ulbikas, and Aasritha Thotakura. Our e-book cover was created by Joy Roasa. During the years, Kay Norwell has always contributed to maintain the book and keep it in online formats. We would also like to thank the staff in the University of Guelph Library for assistance with this newest publishing platform.