Aside from Matthew Scudder, J. P. Keller has always been my favorite of the characters created by Lawrence Block. Keller is just your basic guy, living alone in New York City and doing the sorts of things that a lonely, single guy would do. But every once in a while, his phone rings and it's Dot on the line, summoning him to White Plains to meet with the Old Man. After reporting in and receiving his instructions, Keller then goes off somewhere and kills somebody.
As the book's title would imply, Keller is a hit man, and logically, we readers should be repelled by him and his actions. But as is the case with Richard Stark's amoral thief, Parker, you can't help but root for the guy, even though you know you shouldn't. He's the BAD guy, for god's sake, and we should despise him, but he's just too damned likable.
This is a collection of stories, many of which originally appeared in Playboy magazine, and which were the reason why so many people read the magazine back in the day. They trace the arc of Keller's life through a series of assignments and entanglements, romantic and otherwise.
What makes the character so appealing are his inner musings about life in general and his own in particular. He has a habit of traveling to a small town somewhere and wondering what it would be like to live there permanently; he goes into analysis, but naturally, he can't really reveal anything about himself to the analyst--he has to make it all up. He gets a dog and a girlfriend, both of which complicate his life. He sometimes gets too close to his targets and has trouble carrying out his mission.
It's a complicated life, and in the hands of any writer less skilled than Lawrence Block, the premise would never work. But this is a great collection of stories, and Keller is a character that no fan of crime fiction will want to miss. It's interesting that Block and Richard Stark (Donald Westlake) were close friends and collaborated on a couple of books, and that they would create two great characters like Keller and Parker, protagonists that any right-minded person should revile but that reader can help but love.