Jen Green is a full-time writer with over 350 books in print. She specializes in non-fiction books and websites on history, geography, science, nature and environment. She lives in Sussex, UK. Mark Ruffle was born near Bristol in 1973. He graduated from the University of the West of England with a degree in Graphic Design in 1995. After leaving college Mark worked as a visualizer, then in 1997 started working for Oxford University Press as an Art Buyer. Mark has been freelancing since 2000 and has enjoyed working for a wide variety of clients including Aardman, producing illustrations for Flash. He has designed and illustrated web content for the BBC to accompany television programs such as Hustle, Holby City and Bleak House. Mark works in Adobe Illustrator and is equally happy drawing illustrations for books, packaging, advertising or animation.