Comic Book Classics
When I was young, the first version of a classic book (such as Treasure Island, above) was a Classics Illustrated comic. They were usually 50 pages long or so. I would eventually graduate to reading the original stories, but these sure got me hooked on them from an early age.
Unfortunately these classics in comic book form stopped printing in 1971. My first readings of Mark Twain, Charles Dickens, Robert Louis Stevenson, and others were these comics. I’m not sure if there are any modern day equivalents, but there should be. I’ll look into it.