Here we are! The 500th issue! Bigger (and more expensive!) than normal! And appropriately enough, it's ALL Legion of Super-Heroes. Every one of the stories was previously in ADVENTURE except for the one -off Jimmy Olsen oddity.
Along with Levitz' Legion lore, we get a nice--if woefully short--three page piece from E. Nelson Bridwell in recognition of the milestone. Most likely, the word was already out that the book would only last a few more issues, though.