Do you remember the Encyclopedia Brown books by Donald J. Sobol?
I loved these books as a kid. Rereading the first one as an adult, I found it borders on cheesy.
That does not mean even modern-day kids won’t enjoy the little mysteries Encyclopedia solves for 25-cents each.
Highly recommended for young readers – read aloud as early as kindergarten; a reader probably about 2nd grade, depending on reading level.