What is the best Amazon course/e-book you have ever bought?

One way to quickly understand the strategy of Amazon business is to buy a course/e-book. However, not all of course have good quality. I am a frequent purchaser of course/e-book about Amazon, but only a few are meets my expectation.

Some courses/e-book which I think should be owned are (this is not intended to be promotional but rather as a reference):

- Pshycal Affiliate by Jan Roos - If you concentrate on making multi product web
- Amazonian Profit Plan by Paula and Wanda - If you want to know more detail about creating great in-depth product review.
- Squidoo Niche Blaster - If you’re going to promote Amazon’s product through Squidoo lens.

How about you, guys? Do you have any information on other good Amazon course? Inform it here.