So last night I was reading Count on the Subway (illustrated by Dan Yaccarino) to my daughter. We turned the page and her eyes lit up. Here’s what she saw:

Yep, that’s Doug from Doug Unplugged – a book my daughter and I have read a bunch of times. Doug appears on a poster in the background. My daughter loved seeing a familiar face.

Since the dawn of the dawn, illustrators have been sneaking stuff into their pictures – this includes call-backs to their own work. There are a million examples of this. I don’t know if it’s becoming more popular, but it seems that way, doesn’t it?

The way I see it, there are three main variations on putting your past book in your new book:

1. An image from a previous title appears in your new book. This is what happens in Niño Wrestles the World by Yuyi Morales, which features an image from her book Just a Minute as a puzzle.

2. A character from a previous book appears in a new book. This is what happens in Extra Yarn, which brings in the bear from I Want My Hat Back. Also the new Number One Sam by Greg Pizolli, which features the croc from Pizolli’s The Watermelon Seed.

3. A character from a previous book is hidden in all of your books. This is the Mo Willems approach. Pigeon is in all of them.

So, how do you feel about it? Do you have any great examples?