Elon Musk's first name shows up in 1953 book about colonizing Mars (cnet.com)

I think this book is "Project Mars - A Technical Tale" by Werner von Braun. It's cheaper on eBay, but not much. If you get a chance, read it. It's clearly of it's time, technically, but it definitely shows you a vision of what might have happened.

https://www.amazon.com/Project-MARS-Dr-Wernher-Braun/dp/0973...