I Know, Therefore I Am
Memory by Donald E. Westlake
HardCaseCrime 368 pp. $7.99

This is not your average hard-boiled mystery. There is no crime per se, no detective punching out bad guys and chasing down clues, no gorgeous dame with an inconvenient husband batting her eyelashes. And yet the mystery here is as noir as it gets.

Before we're introduced to the protagonist, Paul Cole, he's been beaten nearly to death by a jealous husband who caught him en flagrante.  When he wakes up he's in the hospital, and he has no idea who he is, where he's from or where to go next.  Released from the hospital and intimidated by the local cops, he decides to skip town and try to track down his former life. 

As he accumulates bits and pieces of information regarding his identity, Cole faces a tragic obstacle of his own memory, which no longer works as it should. He wakes up every morning to a series of notes explaining himself to himself, a la Memento.  The picture that starts to emerge of his life before is at odds with who he seems to be now, but of course, he wants want anyone in his shoes would want, for everything to get back to normal as soon as possible. But if he isn't the man he used to be, who is he?
You'll be thinking about this long after you've finished, and wondering about the nature of identity.
Donald E. Westlake, who died in 2008 ,was an award winning crime writer who wrote under several aliases because he was so prolific. Memory is his last book.