The 1930s was a golden age for comics in many ways. The daily newspaper comics, or "funnies" as they were called, were extremely popular, and had started to expand into a new format -- the serialized weekly comic. Stories like "Prince Valiant" and "Flash Gordon", with their serialized ongoing adventure stories proved extremely popular: other comics like "Dick Tracy" proved that the same serialized format could work in the dailies, too. Comic also weren't just for comic artists: famous painters like Salvador Dali or Picasso got in on the comic scene, using it as a medium for serious artwork.
But more than anything the decade was dominated by Walt Disney: everywhere around the world was launching their own Mickey Mouse Magazine (and some made their own knock-offs).
This decade also saw the debut of a number of legendary comic lines which would become more famous in the coming decades, like "L'il Abner" and "Tintin".