This book could not have been written without the inspiration of my family, mentors, friends, colleagues and students, whom I thank from the bottom of my heart. Certain folk deserve a very special mention. As a kid, my mother inspired me with a love of mathematics and science. My father taught me that theory is fine, but amounts to nought without down-to-earth pragmatism and real-world experiment. I owe so much to Gil Lonzarich at Cambridge who inspired and introduced me to the beauty of condensed matter physics, and to Phil Anderson, who introduced me, as a graduate student, to the idea of emergence and the notion that deep new physics is found within simple yet elegant concepts.

I particularly want to thank my wife and physics colleague at Rutgers, Premi Chandra, who not only encouraged and shared ideas with me, but kept it real by constantly reminding me to think about my audience. At Rutgers, my colleagues Elihu Abrahams, Natan Andrei, Lev Ioffe and Gabi Kotliar receive my special appreciation, who over the years have kept physics exciting and real by sharing with me their ideas and questions, and listening to my own. I also want to especially note my Russian friends and collaborators, who have provided constant input and new insight, especially the late Anatoly Larkin and my two close friends, Andrey Chubukov and Alexei Tsvelik, each of whom has shared with me the wonderful Russian ideal of “kitchen table” physics. Throughout the book, there are various references to the history of many-body physics – here I have benefited immensely over the years, especially through discussion with David Pines, David Khmelnitskii, Lev Gor'kov and Igor Dzyaloshinskii. My apologies to you for any innaccuracies you find in this aspect of the text. I also wish to thank Andy Schofield, who has shared with me his ideas about presenting basic many-body physics. Many others have read and corrected the book with a critical eye, providing wonderful suggestions, including Annica Black-Schaffer, Eran Lebanon, Anna Posazhennikova and my former student Revaz Ramazashvili. Finally, my deep thanks to many students and postdocs who have listened to my lectures over the years, helping to improve the course and presentation.

I particularly want to thank the National Science Foundation and the Department of Energy, who over the years have supported my research in condensed matter theory at Rutgers University.