I don't know if there are other fans here of Letterman & Co, but Bill Carter has a new book out soon:
The War for Late Night
www.amazon.co.uk/War-Late-Night-Early-Te...284733163&sr=1-1
Carter wrote what I found an absolutely absorbing book on this subject a few years ago - called
The Late Shift - which I think is one of the best books on TV that I've read, so I'm looking forward to this one!