I'm listening to a murder mystery on audiobook. I won't say which one until I decide if I like it. The writing is quite good, but I'm not really used to murder mysteries (overlooking the fact that I accidentally published one), and some of the conventions bump me a bit.
The trouble I had with the one today was the author trying to re-re-re-introduce a character who must have been leading this series over the course of several novels. Unfortunately, the author tried to gracefully review Events Thus Far. I heard about the main character's first wife (nice), second wife (not, and missing), acknowledged child, DNA-revealed child, unhappy childhood, previous career, military service, and near-death in a terrible train accident.
I have to confess, when the train accident was mentioned I burst out laughing. It was just too much. Because very little of this backstory meant anything to the immediate story in progress. If I like this book, I will seek out earlier books in the series and learn what I need to learn about this guy, and I will learn it in immediate scene. So there's a tip that applies to all writers, and doubly so to writers of series: backstory has to mean something to the present story. If it doesn't, leave it out.
And whatever you do, don't give the backstory to us in one big lump. It's a bit of a train wreck.