Peter Cheyney 
Ladies Won’t Wait 

Michael Kells is a British secret agent hanging out in France and waiting for his next assignment when he comes across a beautiful woman—almost too beautiful to be true—who seems extraordinarily interested in him. When he finally has a chance to sidle up beside her, he’s a bit surprised when she works the current code phrase into her conversation. “Ladies won’t wait.” They arrange a less public rendezvous, but Kells arrives to find his fellow agent dead.

Following up what few leads he has, he discovers links to the disappearance of another agent, a possible German defector who has been working for the Russians, a highly-sought scientist, and a deadly female agent who will stop at nothing to get what the Russians want…