I also recently finished The Curious Incident of the Dog in the Night-Time, which outlines the entirety of The Hound of the Baskersvilles in one of its chapters. It lists the suspects, the actual perpetrator, the clues, the red herrings: everything! I tried skimming over that chapter in case I ever read the Sherlock Holmes story for myself and wanted to be surprised, but I felt like I was missing out so I had to read it all.
Has a book ever ruined another book for you? Let me know so I can avoid them until I've read the other book!