This is a full-text collection of over 3500 books published by the American Psychological Association. Classic books from other publishers are also included, along with over 1,500 authored entries from the APA/Oxford University Press Encyclopedia of Psychology.
Under the "Research" tab, click on the "Databases" link:
The default "Browse by alphabet" tab allow you to click on "P" in order to locate the PsycBOOKS link:
You may then use the search boxes, or use the "publications" or "browse" links to view available sources.