In 1966 Marvel Comics published a series of "Mini-Books." They measured ⅝" by ⅞" (smaller than a standard-sized US postage stamp!) and were sold exclusively in 10-cent capsule toy vending machines across the United States.
A total of six titles were issued, each of which featured a different Marvel superhero (the Amazing Spider-Man, the Incredible Hulk, the Mighty Thor, Captain America, Sergeant Nick Fury, and Millie the Model) in 50 pages with minimal narration and art. — Read the rest