If you’re looking to build up your home library or to review books before you buy, or if you want to print the classics yourself (perhaps in a large double-spaced font for note-taking and easy focusing) then you’ll want to check out these links:
Free Books Online; Classics
And here are reading lists to help determine which books are appropriate for which age groups
The NEH has divided their list from kindergarten through high school. The College-bound reading list is specifically for high schoolers headed for college. The Kids Reads list begins at birth and goes through high school, too.