It depends how serious you are about it. If you want the best result in terms of improving your learning abilities, and you are praperd to work for it a litle, I recommend the Giordano Memorization system course from school of phenomenal memory. You can read the free manual here:
http://www.pmemory.com/improve_memory-adr.php
You can memorise entire books with this system but it takes some work, it took me a few months to finish the course but I think it's worth it and I don't think there's anything better out there.