The Eiger Sanction is a 1972 thriller novel by Trevanian, the pen name of Rodney William Whitaker.

[1] The story is about a classical art professor and collector who doubles as a professional assassin, and who is coerced out of retirement to avenge the murder of an American agent.

To finance his collection, Hemlock, who served in the Counter Intelligence Corps during the Korean War, works as a so-called "counter-assassin" for a secret US government agency, the CII.

In order to acquire a Pissarro, Hemlock agrees to carry out a couple of "sanctions" (contract assassinations targeted specifically against killers of American agents).

For the second, he will need to join a group of climbers who are about to attempt the north face of the Eiger, a particularly difficult challenge that Hemlock has tried before and failed.