The Indie Author's Guide to the Universe (Kindle Edition)
This book is not groundbreaking, and like any book that deals with the publishing business these days, it is almost obsolete before it comes out; however, there is more than enough great stuff in here to make it not only worthwhile, but a mandatory read for authors just starting out, or any author who needs help with promotion. If you find chapters that don't interest you, or you feel like you don't need that area of help, skip over them. For me, one chapter alone made this book worth ten times what I paid for it. The chapter dealing with product description and how to "sell" your book to the reader on your Amazon page.
I quit reading this book at midnight and went right to the computer and started working on fixing my horrible book description. I believe it's far better now, and it's all due to reading this book. There is plenty of other good advice in here, and I won't attempt to cover all of it, but I would guarantee you that you'll find at least one thing, probably more, that will make this worth far more than what you paid for it.
Giacomo Giammatteo, author of Murder Takes Time