I've just finished reading the book "Doctored Evidence" by Donna Leon, one of the charming Commisario Brunetti mysteries about a police detective in Venice. The plot twist (blackmail, murder) depends on the premise that a key city official has a fake doctorate, and would suffer ruin if that fact got out. So that got me wondering what other books there might be out there. I believe the topic has been mentioned here. The only one I can recall is "Rackety Rax" in which the Mafia starts a fake university, and hires sfootball players, in order to profit from ticket sales. Joel Sayre, 1932, and later a movie. Any others?