Blair Thornburgh is the author of two YA novels, including Ordinary Girls, which came out last month from HarperTeen. Her debut picture book, Skulls!, illustrated by Scott Campbell, is a celebration of the sometimes creepy but always fascinating human skeleton. We asked Thornburgh to let us peek inside her thought process for creating this book, which dates back further than she first realized.

After publishing two YA novels, I didn’t expect nonfiction picture books about anatomy to become part of my body (pun intended) of work. I thought I was a novelist! And definitely not someone who wanted to write books involving any kind of research.

The idea for Skulls! sprang more or less fully formed from my head after a bike ride one day. A coworker commented on the helmet on my desk, and I said, offhandedly, “Well, I have only one head.”

And then I thought: hmm. And then I thought: you know, I don’t think about my skull very often. But I’m sure glad I have one.

I wrote the “manuscript” (I use the term loosely, because I’m pretty sure the text was drafted in a series of Facebook messages to my friend Aimee) in a fit of inspiration, despite the fact that I knew I was flying in the face of all storytelling rules (there are no characters or plot to speak of, really—at least not in the bare words themselves). I also, as I mentioned, felt I had no claim to authority on the subject matter (and may have even said, “I do not want to do any research and am just going to describe skulls off the top of my head”).

I then workshopped the manuscript at a residency during my pursuit of an MFA at Hamline University, where it was suggested to me that: 1) the text might need one more metaphor, and 2) I try making a dummy.

The metaphor became one of my favorite lines: “Like a car seat for your brain.”

Here is the dummy, which I made in our hotel breakfast room at the residency. It leaves a lot to be desired. Especially in the art.

I think including copyright information on handwritten books is always very funny.

My friend Regina also provided some illustrations in the margins of the manuscript.

It all felt very much like a departure from my usual fictional YA fare, until I was asked if I’d always wanted to write nonfiction about anatomy. I said no, but then I remembered something.

As it turns out, this is a topic that has interested me since the completion of my first-ever book: The Body Book by Blair, published in 1994 (at age four).

Sharp-eyed readers will notice that the typesetting has been done by my mother. Presumably the text was dictated. Note also the ersatz triangular pages—undoubtedly too expensive for a traditionally published book.

My drawings leave much to be desired in both their technical precision and their sense of narrative, one of the many reasons I am thrilled to pieces with Scott Campbell’s illustrations in Skulls! He brought that livelihood and delight and character-plottiness that really makes the book what it is. I’m so lucky.

And look at that—I used metaphors! I’m glad that I remembered, as a grown-up, how to write comparisons this oddball.

Hand-drawn colophons and a robust copyright notice are, once and for all, de rigueur.

So perhaps I was always destined to write Skulls! after all.

Skulls! by Blair Thornburgh, illus. by Scott Campbell. Atheneum, $17.99 July 23 ISBN 978-1-5344-1400-6