The Whip Hand (original 1965; edition 2011)

1965 thriller, the first of four featuring private eye Rex Carver. Carver accepts what is presented as a straightforward job of tracing a young woman, and ends up chasing around Europe in a murky plot where he's working for at least three different masters who may or may not be on different sides, and include at least one official intelligence organisation. Definitely a product of its time, in more ways than one, but good fun and well worth a read. ( )