I really enjoyed reading Live From New York. It tells the 25-year history of Saturday Night Live as a series of interview excerpts with the principal cast members, writers, and producers.
There are a lot of terrific backstage stories from the first season as well as insight into the various cast changes that have happened over the years. You really get a sense of what the production cycle is for a weekly variety show like SNL, and how unique the show is in network television, both when it first appeared, and in the current era. You also get to read where a lot of the innovative ideas for the show came from, like the "cold open" which nobody had done before and is sort of a trademark of the show.
One thing I didn't realize is that Larry David used to be a writer on the show, and could never get his scenes into the show. He was so frustrated that he quit in front of everyone at the read-through when they pick which scenes to work on for the show. While he was walking home he's thinking about how much money he's giving up, and how he can't really quit. So, he decides to come in the next week and pretend that it never happened. That really happened! It wound up in a Seinfeld episode.
If you're interested in comedy, show business, late night television, or improvisational troupes like Second City or the Groundlings, you should really read this book.