Nothing in Her Way by Charles Williams -- pdf
 
  Charles Williams was an American writer of hardboiled crime fiction. He is regarded by critics as one of the finest suspense novelists of the 1950s and 1960s. His 1951 debut, the pulp paperback novel Hill Girl, sold over a million copies. A dozen of his books have been adapted for the screen, most popularly Dead Calm.
  --Wikipedia

  Nothing in Her Way is about a series of con games, with so many double crosses, triple crosses, and quadruple crosses that it will almost certainly keep you off balance all the way through.  You may think you know who's doing what to whom, but Williams is consistently surprising.  Even at the end, you might not be sure who wins, but you'll know who the loser is, another guy who trusted a woman who's a lot colder and smarter and more ruthless than he'll ever be.  And another great ending, too. 
  --Bill Crider