I don't think I've ever read a novella before.
As a pretty slow reader I enjoy the novelty of knocking out a book in a single sitting.
I'm sure that the format of a novella; its brevity and concision, lends itself perfectly to some stories. Hey, it might even do so for the tale of a Scottish detective and a missing person. But I'm not convinced it particularly works for Rebus.
Maybe that's just because, eight books in, I'm used to a certain rhythm to a Rebus story, one which can't really be achieved with this word count. A Rebus book is always playful with how it tells the story - there's always a number of different plot lines - often conflicting, calling out for our protagonist's attention and pushing him into impossible corners. And Rankin teases out these plot lines giving you a little at a time, never giving you the full picture until he has to. These sub plots work in solidarity to enhance the overall story, and their absence was the most striking thing to me about 'Death is Not the End' - leaving it feeling a little simplistic and ultimately unfulfilling.
It's an entertaining enough little story - we get a few glimpses into Rebus' childhood, meet some people from his past, get the eureka moment as he (alongside Farmer Jim) solve the crime. It's just that there wasn't a huge amount of mystery or high stakes surrounding the crime in the first place, I doubt we'll see the people from his past again, and his childhood story doesn't really change anything.
Happy to have read it, but it's far from the first Rebus book I'd recommend to a new reader.