Parodying specific targets became a staple of "Mad". Beginning April 1954, the bimonthly "Mad" went monthly after the cancelation of "Frontline Combat", whose sales had flagged when the Korean War ended. Soon, large numbers of "Mad" imitators sprang up from other publishers, as well as from EC itself with the Feldstein-edited "Panic". Kurtzman poured himself into "Mad", putting as much effort into it as he had into his war books. This defeated the purpose of having an easy-to-produce third book, but with "Frontline Combat"s cancelation, Kurtzman focused on "Mad".