Some children want to crack the case themselves — hunt the clue everyone else walked past and catch the culprit before the last page. These are the great solve-it-yourself mysteries and child-detective series. Any one of them satisfies this shelf, so pick by what fits your child right now, whether that's a brand-new reader sounding out a first case or an older one ready for a full historical whodunit.
Every book is a self-contained mystery a child can play along with, and they're arranged only loosely by age so you can find the right fit fast. At the easy end are the classic solve-it-yourself detectives, Nate the Great and Encyclopedia Brown and Cam Jansen, where all the clues are on the page and a young reader gets to beat the detective to the answer. In the middle sit the funnier and cleverer ones, Timmy Failure's deadpan comedy and Chasing Vermeer's pattern-puzzles. At the top are the two with real weight, the Benedict Society's menacing villain and Enola Holmes's genuine danger, for a child who's ready for a mystery that bites back. Hand over whichever one matches the child in front of you.