Improv Nation: How We Made a Great American Art (by Sam Wasson)

A history of improv, from the Compass Players to Anchorman.  Deeply researched and a lot of interesting tidbits*, although I feel the writing is flawed.

For one, it seems a bit over-written, with some florid sentences and tortured metaphors. I got the sense this was just Wasson's style, but it sometimes was distracting.  The information is also presented in a fragmented way, jumping around among different groups and people from paragraph to paragraph.  And my final complaint: not enough specifics about the structure of improv itself. 

In a way, it's a result of having so much to cover -- you could easily write a 500 page book just about Christopher Guest movies or Gilda Radner or Nichols and May. (I would read all of these books.) So it's definitely worth a read if you're interested in the topic, but expect to jump around a bit.

*My favorite one: Bob Odenkirk wrote the original "living in a van down by the river" Matt Foley sketch with Chris Farley when they were at Second City.