Paul B. Wignall is professor of palaeoenvironments at the University of Leeds. He has been investigating mass extinctions for more than twenty-five years, a scientific quest that has taken him to dozens of countries around the world. The coauthor of "Mass Extinctions and Their Aftermath", he lives in Leeds.

Jonathan Cowley is a British actor living in Los Angeles who has received AudioFile Earphones Awards for his narrations of The Science of Evil by Simon Baron-Cohen and The Tower, the Zoo and the Tortoise by Julia Stuart.