Six Days of the Condor

The novel that inspired the Robert Redford film Three Days of the Condor.
Sandwiches save Ronald Malcolm's life. On the day that gunmen pay a visit to the American Literary Historical Society, he's out at lunch. The Society is actually a backwater of the Central Intelligence Agency, where Malcolm and a few other bookworms comb mystery novels for clues that might unlock real life diplomatic questions. One of his colleagues has learned something he wasn't meant to know. A sinister conspiracy has penetrated the CIA, and the gunmen are its representatives. They massacre the office, and only learn later of Malcolm — a loose end that needs to be dealt with.
Malcolm — codename Condor — calls his handlers at the Agency, hoping for a safe haven, instead drawing another attempt on his life. With no one left to trust he goes on the run. But like it or not, Malcolm is the only person who can root out the corruption at the highest levels of the CIA.