At UnBeige, mediabistro.com's design blog, Stephanie Murg informs us that it's the 40th anniversary of The Hungry Little Caterpillar, a classic children's book by Eric Carle that's sold more than 12 million copies in 45 languages:

The famed caterpillar actually began his life as an ordinary worm [Stephanie reports]. After some fortuitous experimentation with a hole puncher, Carle got to thinking about a bookworm and created A Week with Willi Worm, which ended with the title character growing into a morbildy obese worm. "I showed it to my editor, Ann Beneduce, and she didn't like the worm so much," explains Carle in a video on his website. "She said, 'How about a caterpillar?' And I said, 'Butterfly!'" And the rest is history."