Books like The Flash of Two Worlds

If you love Silver Age comics as much as I do, you can't go wrong with this one (Flash #123). Gardner Fox manages to avoid the repetition and the bourgeois over-magniloquence/self-indulgence he used in other titles such as Hawkman (with Joe Kubert) and Batman ("Robin you need to go to university to study!"), giving us instead a story with a tight and simple plot and a simple yet intruiguing introduction to the concept of multi-earths, which oddly enough will be the at the base of the convoluted garbage known as Crisis on Infinite Earths. Take confidently this awesome comic one million times over Marv Wolfman's crapsterpiece.Edit: rating dropped of 1 star because the main device behind this story is not original (Look at William Moulton Marston's Sensation Comics #30 for that), but it's a required and good read nonetheless.