Cornell Woolrich is the author of the gloomy and excellent revenge noir, Rendezvous in Black. I loved it so much I named it the best book I read last year. The Case of the Mexican Knife, also written by Woolrich but under the pseudonym Geoffrey Holmes, didn't float my boat quite as much as that one, but it's a solid, south of the border, straight forward noir, which is to say, the plot is not straight forward at all.
There are twists and turns and back stabbings and mysteries and I even at one point had two characters completely mixed up for a few chapters, but it's all just great escapist fun. Having lots of bummer dental work done? Sick of catty people being rude to you? Whatever ails you, just pop open this (sadly waaaay out of print) book and read the tale of one, Mitchell Drake, a teacher living in the US who goes back to his home country of Mexico to find his missing brother.
Once there he finds one body after another and many shady and unknown enemies with plans to kill him. He's being followed and following, he's being beaten and shot at but the whole time all he can think of is the student he's in love with who is also in Mexico, but is herself in love with a no good double crossing revolutionary.
This archetypal pulp novel was also published under the pretty darn awesome title The Street of Crying Woman.