J.W. Rinzler is the author of The Making of Star Wars: The Empire Strikes Back, an almost 400 page book full of all-new photographs and drawings detailing the making of the movie thirty years ago. The book is released this Tuesday.

Two fun facts from the rich fund of the book are:

1. Yoda was originally to be played by a monkey in a mask:

When George Lucas and screenwriter Lawrence Kasdan decided to make the ancient Jedi at the heart of Luke's spiritual journey into a two-foot tall, pointy-eared alien, it wasn't clear how the character could actually be realized on screen using 1980 technology. At the time, animatronic technology wasn't thought to be advanced enough to pull off Yoda.
So...they decided to try putting a trained monkey in a Yoda costume, including a full Yoda face mask. Rinzler showed a picture of the monkey on set, but he explained this idea was quickly abandoned when one of the people who worked on the primate scenes in 2001: A Space Odyssey pointed out "Look, the monkey's just going to pull off the mask over and over again. It's never going to work."

2. The person who played Palpatine in the short holo-scene in TESB was never officially named. But:

Clive Revill ultimately voiced the character, but all that was known about the person behind the mask was that she was an unidentified woman in heavy prosthetic makeup.
Now we finally know who played the character - it was Elaine Baker, the then-wife of long-term Star Wars makeup designer Rick Baker. Considering Rick Baker put the gorilla suit on for the 1976 King Kong remake, this means Emperor Palpatine was once married to King Kong. I'd say the world is definitely a better place for us knowing that.

I agree!

I am definitely getting this. Maybe not as soon as it comes out, but sooner or later!