A good picture book is like theater.

You’re probably familiar with The Caldecott Medal (awarded annually to the artist of the most distinguished American picture book for children).

But who is this Caldecott exactly?

Beatrix Potter called him, “one of the greatest illustrators of all.”

Maurice Sendak credited him with inventing the modern picture book.

Sir Randolph Caldecott (b.1846) was a British artist and illustrator who changed children’s books forever. He juxtaposed word and image in a way they never had been before. Sometimes he let the pictures do the storytelling, sometimes the words.

And he used the page-turn in his books in a way no one had before. Turn the page and you found some pages were just line drawing. Others were full-color. Some pages only one drawing. Every page was different. You never knew what was coming next. The page turn was as integral to the story as words or image.

And ever since that has been the hallmark of a good picture book. As you turn the page it is as if a curtain is being raised and you never quite know what is coming next.

The endpapers (the pages at the start and end of the book) operate like the trailer of coming attractions. In a good picture book—just like the titles in a Hitchcock film—they clue you in to what might be coming.

It’s one of the reasons I think digital won’t ever replace picture books. Because books can do at lease one thing far better than any iPad or Kindle: the beautiful simple turn of the page.