Walls: The Long History of Human Barriers and Why We Build Them (Hardcover) (ISBN-13: 9781459833111)

Gregor Craigie is a radio journalist and writer. He has worked for the Canadian Broadcasting Corporation for many years. Before that he worked in several cities, including London, England, where he was an announcer for the BBC World Service and a reporter for CBS Radio. Gregor's first book for adults, On Borrowed Time: North America's Next Big Quake, was a finalist for the Writers' Trust Balsillie Prize for Public Policy and the City of Victoria Butler Book Prize. His first book for children was Why Humans Build Up: The Rise of Temples, Towers and Skyscrapers, part of the Orca Timeline series. He lives in Victoria, British Columbia.

Arden Taylor is a Toronto-based freelance illustrator. A graduate of Sheridan College with an honors bachelor of illustration, she enjoys digitally creating colorful illustrations of architecture and people and designs for wallpaper and other projects. Her clients include Hazlitt Magazine and the California Institute of Technology, and her work has been featured in various magazines, newspapers, advertising campaigns and websites.