Getting Off: A Novel of Sex and Violence (Hard Case Crime #69) by Lawrence Block. I'm pretty sure someone here recommended it recently, and as a fan of Block I was intrigued, and when I saw the cover I was hooked
About a female serial killer with a lot in common with the black widow spider and the praying mantis... Like all of Block's books, it is a fun read.
When I've finished this, I'll be moving on to
Just One Damned Thing After Another by Jodi Taylor, as recommended by Samhy.