What books get you out of your reading slump?

I've been in a horrible reading slump for years. I was fine with audiobooks and podcasts but just couldn't concentrate on reading.

Finally I've found that Agatha Christie novels hold my attention - they are fast paced, not overly complicated, and got me interacting with the story as I played detective while taking notes on the clues in the story.

Now that my reading muscle memory is coming back, I'm able to branch out to more complex books.

What type of books break your reading slump?