I ordered this book in January for my coursework in Spring 2010. The book was a valuable resource that my instructor referenced often. I find it unlikely that this will be the type of text that you buy and crack maybe twice during the semester. I bought it new, it arrived in perfect shape in shrink wrap.
I agree with comments stating how most of the concepts and theories are backed by research. It is also very readable as far as textbooks go, the author does not try to overwhelm the reader with technical jargon and unfamiliar concepts. It is a good primer for ethologist minded people, or for those interested as part of a greater understanding of animals.
I am pre-vet and even though this course was not recommended or required by graduate school, I am glad I took the class. It was very enlightening.