The policy paper emphasizes a public health perspective.
There are also a lot of resources available on the Web that can support clinical care in major depression.
Materials for self-management have been developed by Dr. Dan Bilsker at Simon Fraser University and are freely available here.
An on-line version of CBT is freely available here, from the Australian National University. This version of computerized CBT was evaluated in a randomized controlled trial published in the British Medical Journal, link here.
Wikepedia has alot of information too, including definitions and history, here.
It includes a picture painted by Van Gogh in the year of his suicide.