A detailed booklet that describes symptoms, causes, and treatments, with information on getting help and coping.

It is available in pdf format, there is a printer-friendly option or you can read it online.

It is simply called Depression and the sections include:

What is a Depressive Disorder?
Types of Depression
Symptoms of Depression and Mania
Causes of Depression
Diagnostic Evaluation and Treatment
How to Help Yourself If You Are Depressed
Where to Get Help
Further Information