The Parsifal Mosaic by Robert Ludlum

The Parsifal Mosaic is a 1982 spy thriller novel by Robert Ludlum about a CIA agent, Michael Havelock, who goes on the run after his partner and lover, Jenna Karas, is seemingly killed. He is then forced to race across the globe to uncover a vast conspiracy orchestrated by a mole known as "Parsifal". The novel is notable for its intense focus on the Cold War and the threat of nuclear war.