Mark Hallett is a naturalist, scientific artist, and author who specializes in prehistoric animals and their environments. His art and writing have appeared in
Life,
Smithsonian, and
National Geographic. He is coauthor of
Seismosaurus: The Earth Shaker (Columbia, 1994) and
The Sauropod Dinosaurs: Life in the Age of Giants (2016), among other works.
John M. Harris is chief curator emeritus at the Natural History Museum of Los Angeles County and visiting associate in geology at the California Institute of Technology. He is coeditor of
Laetoli: A Pliocene Site in Tanzania (1987) and
Lothagam: The Dawn of Humanity in Eastern Africa (Columbia, 2013).