Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Block at his best

Dark, wry, hilarious, sad . . . one of my favorite writers at his best! In Keller, Block creates a unique blend of innocence and evil, a hitman that is credible, creepy and endearing all at the same time. How DOES he do that?It's inspiring to see a writer like Block, who has been prolific for many decades, continue to get better and better. This is one of those books that transcends genre. Recommend it to your literary friends. I'm definitely staying tuned.Oh, and btw, does anyone else see Mick Ballou of the Matthew Scudder series as the percursor to Keller?