I have benefited from the contribution of many individuals who have made it possible to write this book. I am grateful to my patients who over several decades have taught me with their life stories the importance of mind-brain-gut interactions for health and disease. To my incredible colleagues and research team who were essential throughout my career in pursuing the research on the interactions between the gut, its microbiota, and the brain. To Paul Bell, Sue Smalley, and Barb Natterson, who encouraged me to embark on writing this book and whose encouragement helped me to complete it. To Rob Lemelson and Marco Cavalieri, who with their incredible generosity provided beautiful physical spaces to start the creative writing process. To Dan Ferber for invaluable advice and assistance that helped me to put a wealth of hard science into an easily readable and entertaining text, and to Sandra Blakesley, Billi Gordon, and Royce Flippin for their creative input. To Mark Lyte for help with historical aspects of the gut-microbiome signaling story. To Marco Cavalieri and Nancee Chaffee for practical advice on the topic of the Mediteranean diet. To Catherine Cowles, my agent, who introduced me to the world of publishing for a wide audience and to Julie Will, my editor at HarperWave, who put her faith into my book proposal from the very beginning and provided me invaluable editorial advice throughout the process. To Jon Lee, for creating the illustrations for the book. And last but not least to my wife, Minou, who not only encouraged me to keep on going during difficult phases of the writing process, but who was incredibly supportive by putting up with an “absent” husband during the past year.