In Deep Ancestry, Spencer Wells, the director of the National Geographic Society's Genographic Project, clearly explains the science behind the project — which is collecting DNA from a wide sample of the world's population in order to understand the evolution of the human genome — and also engagingly relates the stories of five of its volunteers. Describing the book as "concise and well-written," the reviewer for Publishers Weekly writes, "It is a remarkable journey that will appeal to readers of all backgrounds interested in exploring the science and research behind human evolution." Wells's first book was The Journey of Man.