Never heard of it? I'm not surprised, there were only a handful of english-language print runs. If you were lucky enough to buy it as a kid, I hope you held on to it.
Not as a collectable, mind you, but just because it's so unique. It's not a story-book, activity book, or even a Muppets character resource,
If you've never seen it, it's pretty much the first two seasons of The Muppet Show in illustrated form.
The art is just outstanding and the gags are still funny. As a kid, I think this was the closest thing I could have possibly had to a portable DVD player full of Muppet sketches.
If you don't believe me, watch this:
It's just as funny in the book, imagine that?
Not my scan, copied from http://www.amazon.com/gp/customer-media/product-gallery/B000H9LTE0/ref=cm_ciu_pdp_images_1?ie=UTF8&index=1
I spent hours and hours with the book while traveling, when I was sick and when I just wanted to have a good time.
Maybe the ultimate book for an introvert with a whimsical sense of humor.
If you want to find our more about this great book, I direct you the Muppet Wiki.