Citing books and textbooks follows the examples in the manual in section 7.02 Books, Reference Books, and Book Chapters (p.202). Rule #18 should be followed when citing an entire print book. Rule #20 is a good one to follow for electronic books.
Here's an example of the format for citing books:
LoBiondo-Wood, G., Haber, J., Cameron, C., & Singh, M.D. (Eds.). (2009). Nursing research in Canada: methods and critical appraisal for evidence-based practice. Toronto, ON: Mosby/Elsevier.
This particular example is a course textbook, and is also an example of referencing a book with editors.
Section 7.02 also covers book chapters and articles from reference books. Rule #25 covers book chapters and rules #27-30 cover the various forms of reference works.
Here's an example of how to cite a book chapter, using the same example as above:
Haber, J., & Cameron, C. (2009). Developing research questions, hypotheses, and clinical questions. In LoBiondo-Wood, G., Haber, J., Cameron, C., & Singh, M.D. (Eds.). Nursing research in Canada : methods and critical appraisal for evidence-based practice. (pp.65-89). Toronto, ON: Mosby/Elsevier.
Note that the second and subsequent lines should be indented, to emphasize the author (not shown in the examples above due to html formatting).
All information and page number references are based on the 6th edition of the Publication Manual of the American Psychological Association (2009/10).