For a long while, I checked the Amazon free lists every day or two and downloaded any books that were about book marketing. As a result, I’ve read a lot of them. Most are decent for beginners, but don’t provide anything you couldn’t easily find out for free. A few, however, are excellent and well worth whatever you have to pay for them.
Here are my top 4:
Your First 1000 Copies: The Step-by-Step Guide to Marketing Your Book by Tim Grahl
Sell More Books! Book Marketing and Publishing for Low Profile and Debut Authors: Rethinking Book Publicity after the Digital Revolutions by J.Steve Miller and Cherie K. Miller
Let’s Get Visible: How To Get Noticed And Sell More Books by David Gaughran
Write. Publish. Repeat. (The No-Luck-Required Guide to Self-Publishing Success) by Sean Platt and Johnny B. Truant
Read all these books and you will know more about book marketing than 90% of authors.