Before jumping into in-depth research on a topic, it's important to have background information to gain a better understanding of your topic.  You can think of this gathering of background information as "presearch."

Books are a great source for detailed information.  Check out the suggested E-Book Collections to cross-search numerous e-books at the same time to find pertinent, reliable information.

Use these databases to access individual books, as well as cross-search numerous books for the most relevant information.

Health & Medical Specific Collections:

General Ebook Collections:

To find reliable information, from trusted sources, consider using: