It's also on amazon https://www.amazon.com/Exploration-Map-Migrations-Encounters...

There is a kindle version (which would be closer to epub than pdf) but it just is even worse than a pdf and the authors also include the reason for that:

> Due to the complex integration of images and text, this DK eBook has been formatted to retain the design of the print edition. As a result, all elements are fixed in place, but can easily be enlarged by using the pinch-to-zoom function.

EPUB is simply not ready for complex layouts.