Behind the scenes of Gastronauts, part 3: cover design

My new book Gastronauts is out now in bookstores and online.

Today I’m taking you behind the scenes to show you how I designed the robots and vehicles in the story.

Quick recap: Sally Tinker is the world’s foremost inventor under the age of twelve. In Gastronauts, Sally’s baby brother Joe swallows her latest invention. So Sally and her friend Charli shrink themselves down in a tiny submarine and journey into Joe’s body.

Here’s how I designed the cover.

Step 1: really bad first sketches

Sometimes you get the cover idea pretty quickly and clearly from the start.

This was not one of those times.

I struggled with this a lot at first; I couldn’t figure out how to show the reader that Sally and Charli were inside a sub, inside Joe, and make Sally and Charli big enough so that they were recognisable, without being too big that the scale stopped being anatomically correct.

None of these ideas really work, but I’ve included them here to show you how a cover design process can go. There are usually lots of rejected, fairly ordinary ideas.

Step 2: some marginally-better-but-still-not-great sketches

My amazing editor Cate suggested using one of the internal illustrations as inspiration, and having Joe’s mouth on the cover like so:

I set about simplifying that idea down to fit into a portrait-orientation cover, while increasing the size of Sally and Charli’s SUB.

This was before I had figured out that the legs and claws would retract.

It’s unfortunate, because it looks like Joe is eating a metal crab. Which really creeps me out.


None of these ideas worked either. But what if we flipped the camera around so it was at the back of Joe’s throat pointing towards his mouth?

Step 3: getting closer but not by much

Here are my attempts to make the internal camera angle work.

This one was again drawn before I figured out that the legs and claws on the SUB could retract.

With saliva:

and without:

Then once I redrafted the story and figured out the SUB would have retractable legs and claws, I redesigned the cover like so:

Then upped the colour saturation like so:

I thought that would be the cover. But it still kinda didn’t work; the reader needed to be able to tell they were inside the human body immediately, and that didn’t happen with this cover design. Maybe if I’d included a full set of teeth it would have been easier, but baby Joe is, well, a baby, and only has a few teeth. So it was back to the drawing board for a completely different idea.

Step 4: final rough design

Here’s the final sketch; the SUB inside the bloodstream.

This cover design had two benefits:

1) they’re very obviously inside a body

2) it meant we could have a strong focus colour; red.

Here’s the colour mock-up, showing all that glorious red. It’s such an eye-catching colour for a book cover. I’m glad we went through all the rough versions we did, because it meant we got to something better.

Here’s the final cover for comparison:

I hope you liked this behind-the-scenes look at the making of Gastronauts. If you’d like to see more behind-the-scenes posts, click here.



Buy local – find your closest bookshop

Or order online:
– Booktopia (Australia and NZ only)
Angus and Robertson (Australia only)
QBD (Australia only)
Book Depository


Author: James Foley

James Foley makes children’s books for children who read books. If you’re a child and you’re eating his books, you’re doing it wrong. His books include Brobot, Dungzilla, Gastronauts, Chickensaurus, Toffle Towers, My Dead Bunny and There's Something Weird About Lena. James lives in Perth with his wife, 2 kids, and a labrador. He is a massive Marvel movie nerd and comes from a long line of queuing enthusiasts. Follow him on FB/twitter/insta/youtube @jamesfoleybooks, or at .

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