Today sees the release of J.W. Rinzler's The Making of Star Wars: The Empire Strikes Back. Rinzler also wrote The Making of Star Wars: The Definitive Story Behind the Original Film, which explored the creation of A New Hope. If you want to pick this new treasure trove of Empire history online, Amazon has it for $45.90 (almost half off the list price), which appears to be the best price out there.
In addition, be sure to read io9's recap of J.W. Rinzler's New York Comic-Con panel about the book. Who knew that Lucas considered "putting a trained monkey in a Yoda costume, including a full Yoda face mask"?
UPDATE: Here are a few more stories about the book.
The Star Wars Aficionado blog has an interview with J.W. Rinzler which you can read here. (Thanks Scott!) And io9 revisited the subject with a list called "10 things you didn't know about The Empire Strikes Back." Check that out here and see if they're all revelations for you. (Thanks Tracy!)
UPDATE #2: Here's one more interview link as Pete Vilmur chats with J.W. Rinzler over at SW.com.
Rebelscum Breast Cancer Awareness Charity Patch Posted By Philip on November 25, 2014: Thanks to everybody that ordered patches. I sent a check for $1,600.00 to the National Breast Cancer Foundation on Monday. While it's not as much as I hoped for, it's still very much appreciated. They will remain for sale in the store for anybody that still wishes to purchase them. Details after the jump.