These actually took me most of 2013 and 2014 to get through:

How To See Color And Paint It - http://www.amazon.com/How-Color-Paint-Arthur-Stern/dp/082302... Taught me how to paint what I see accurately.

Secret Knowledge - http://www.amazon.com/Secret-Knowledge-New-Expanded-Rediscov... Taught me that painters have been using projection for hundreds of years so I'm allowed to use any technology I can get my hands on to make art.

Van Gogh: The Life -- http://www.amazon.com/Van-Gogh-Life-Steven-Naifeh/dp/0375758... Hated this book because the authors (two obnoxious lawyers who happen to be good at research) write about him with zero compassion like he deserved the abuse he received for being different. However, Van Gogh's story is fantastic and inspiring even if it is very tragic.

There's a whole ton of others, but those stand out.

The 2006 monograph by the british artist David Hockney (for anyone interested).

Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters[1]

[1] ISBN-10: 0142005126> http://www.amazon.com/Secret-Knowledge-Expanded-Edition-Redi...