Wow, The Simpsons has been around a LONG TIME! Right now, they're on Season 15 and the hit show doesn't look like it will end anytime soon. Of course, the episodes are kind of stupid now and some are losing interest. The Simpsons Beyond Forever covers season 11 and 12. The book is basically a really detailed episode guide. Inside, there is an Itchy and Scratchy Filmography, Homer's D'OHS! and his mmm's, and of course, the couch gags. But, that's only part of the book.
Also, they tell everything you need to know about each episode in seasons 11 and 12. There's the stuff Bart writes on the chalkboard, quotes from the episode, a summary and hilarious pictures. With 2 pages for each episode, they have plenty of room to fit anything they want on it. They even do a The Stuff You May Have Missed section for every episode. They have even more information for the Treehouse of Horror episodes. 4 WHOLE PAGES! The episodes aren't even that great!
The book, I wouldn't consider short, but not long. The first book(The Simpsons) almost has 100 more pages than Beyond Forever! But, Beyond Forever has enough information that the few pages don't really matter.
You'll find EVERYTHING you need to know about season 11 and 12 in this book. Basically, it's amazing. I would reccommend this true work of art to any Simpsons fan. You could watch one Simpsons episode and still find this book interesting. Seasons 11 and 12 weren't included in the drop of ideas that has suddenly come into The Simpsons. The wonderful episode HomR lets you discover Homer's only stupid because he lodged a crayon up his nose as a kid. Plus, there's the crazy Trilogy of Error episode where it tells where Homer's finger was cut off by Marge and her brownies.
All in all, this book is AWESOME! Buy it.