Book excerpt: The author of the New York Times bestseller This Is Your Brain on Music reveals music’s role in the evolution of human culture in this thought-provoking book that “will leave you awestruck” (The New York Times). Daniel J. Levitin's astounding debut bestseller, This Is Your Brain on Music, enthralled and delighted readers as it transformed our understanding of how music gets in our heads and stays there. Now in his second New York Times bestseller, his genius for combining science and art reveals how music shaped humanity across cultures and throughout history. Here he identifies six fundamental song functions or types—friendship, joy, comfort, religion, knowledge, and love—then shows how each in its own way has enabled the social bonding necessary for human culture and society to evolve. He shows, in effect, how these “six songs” work in our brains to preserve the emotional history of our lives and species. Dr. Levitin combines cutting-edge scientific research from his music cognition lab at McGill University and work in an array of related fields; his own sometimes hilarious experiences in the music business; and illuminating interviews with musicians such as Sting and David Byrne, as well as conductors, anthropologists, and evolutionary biologists. The World in Six Songs is, ultimately, a revolution in our understanding of how human nature evolved—right up to the iPod.