To Kill a Mockingbird Book | Harper Lee- honestly one of the best books I've ever read. Really gives insight to life at the times. I recommend the book for summer reading, grades 7 and up, but anyone younger should ask a parent first, because of some language and other things.
Enid Blyton - the Famous Five. Old-school? Yes. Twee? Yes. Fantastical? Yes. It still doesn't make us love Enid Blyton's series any less. All the best things about Old Britain, condensed into a narrative.