Christopher graduated with a double first in history from Cambridge in 1990 and went on to become the Technology Editor for The Sunday Times newspaper in London. He is now a best-selling author of more than 15 books on world history including What on Earth Happened? The Complete Story of the Planet, Life and People from the Big Bang to the Present Day (Bloomsbury) and the series of What on Earth? Timelines. He divides his time between writing, running the business and giving talks at festivals, schools, home education groups, and in stores.