It’s unusual for a book from the 40′s to still be on the bookstore shelves, but Make Way for Ducklings by Robert McCloskey is an exception. Not just because of its timeless story, but also because of its Caldecott Medal.

The Caldecott is given each year “to the artist of the most distinguished American picture book for children.” It’s the illustrator who receives the award, but the book as a whole has to be superior, as well. So this week, I decided to find out what makes a book a Caldecott. It’s been enlightening.

The thing about Caldecotts is that they generally stay in print. So you have a sampling of books from the last 70 years. It’s amazing how much picture books have changed. And how much they haven’t.

Take the 2005 Caldecott Medal winner, Kitten’s First Full Moon by Kevin Henkes. This book has a simple, sweet story about a kitten mistaking the full moon for a bowl of milk. The pictures have a clean and simple style with bold lines and soft, night time colors. This book could’ve been created at anytime, ever since cats have been gazing up at the moon. It has a classic feel with a lovely, traditional picture book story and structure. Picture books haven’t really changed.

But they have. And Smoky Night illustrated by David Diaz and written by Eve Bunting shows this clearly. This magnificent story takes us out of the normally safe and snug domain of picture books and throws us into the middle of a riot. These are not ducklings at stake either, but children, families, and neighborhoods.

Styles change too. This year’s medal book, Flotsam by David Wiesner is a complicated story told completely with bright, detailed, funny pictures. Wordless picture books aren’t new. But Flotsam is an good example of how pictures have started taking on new importance and complexities in childrens’ books, as texts get shorter and illustrations start creeping (wonderfully) into older and older childrens’ books.

So, looking at all these picture books, have they changed over the years? Ummmmmm, excellent question. But unfortunately, I have an urgent appointment I just remembered. Gotta go!

Take a look at other Caldecott greats I read this week: Where the Wild Things Are by Maurice Sendak, Tuesday by David Wiesner, The Snowy Day by Ezra Jack Keats, Olivia by Ian Falconer, Sylvester and the Magic Pebble by William Steig, Jumanji by Chris Van Allsburg, Click, Clack, Moo: Cows that Type written by Doreen Cronin and illustrated by Betsy Lewin.