Some things to remember when using information from books:
If you're citing a book, are you using the most recent edition?
Depending on your topic, using an older edition can be problematic because advances in knowledge and theory may invalidate the information. Think of it this way...would you use an edition of Harrison's Principles of Internal Medicine from 1980 in your clinical decision making?
Pay attention to the date the article or book was published. Some questions to consider include:
Do you need the most current information?
Example: You’re looking for recent information on diagnoses, treatments, etc.
Do you need historical information?
Example: If you’re comparing the infant “back to sleep” campaign for mothers to put babies to sleep on their backs with the
older recommendations to put babies to sleep face down.
Are you looking for “trends”?
Example: You’re looking for information on the trend to “NOT” treat minor pediatric ear infections with antibiotics.
If you're writing a topic overview you'll probably want to include more recent information, but it's also important to include seminal works regardless of whether or not they are dated.