The Paranoids refer her to The Courier's Tragedy, a play that she sees and after which the mystery begins.  
In this novel the protagonist's husband has recently become a disc jockey for KCUF radio, and her psychiatrist admits to having been a Nazi doctor at Buchenwald.  The Paranoids refer her to The Courier's Tragedy, a play that she sees and after which the mystery begins.  In the course of executing the will of Pierce Inverarity the protagonist meets the inventor John Nefastis and the stamp expert Gengis Cohen.  Ending with the anticipation of the titular part of an auction at which Oedipa Mass hopes to discover more about the Tristero, FTP, name this novel by Thomas Pynchon.
In this novel the protagonist's husband has recently become a disc jockey for KCUF radio, and her psychiatrist admits to having been a Nazi doctor at Buchenwald.  
The Crying of Lot 49