I decided to change the question to PRODUCTS instead of books.

The best copywriting products I have read...

1. How to Turn Your Web Site Into An Unstoppable Sales Machine! by Marlon Sanders (His bullet writing method is the one I use.)
2.The Robert Collier Letter Book
3. Breakthrough Advertising -- Eugene Schwartz
4. AWAI Copywriting Course
5. How to Write a Good Advertisement by Victor O. Schwab
6. Triggers by Joe Sugarman
7. 2,239 Tested Secrets For Direct Marketing Success by Denny Hatch
8. Method Marketing by Dension Hatch
9. Tested Advertising Methods
10. Scientific Advertising