I would like to thank here a number of people to whom I am indebted in one way or another. To begin, there are five people from whose insights I especially benefited in my formative years in physics. In order of appearance: Sze M. Tan, for teaching me classical measurement theory, and introducing me to information theory and thermodynamics; Howard M. Wiseman, for teaching me about quantum measurement theory; Salman Habib, for teaching me about open systems and classical chaos; Tanmoy Bhattacharya, for enlightenment on a great variety of topics, and especially for the insight that measurement is driven by diffusion gradients; Gerard Jungman, for mathematical and physical insights, and for introducing me to many beautiful curiosities.

I am very grateful to a number of people who helped directly to make this book what it is: Os Vy, Luciano Silvestri, Benjamin Cruikshank, Alexandre Zagoskin, Gelo Tabia, Justin Finn, Josh Combes, Tauno Palomaki, Andreas Nunnenkamp, and Sai Vinjanampathy who read various chapters and provided valuable suggestions that improved the book. Xiaoting Wang who derived Eqs. (G.43)–(G.48). Jason Ralph who enlightened me on some superconductor facts that were strangely difficult to extract from the literature. Jason also helped me with the brief history of superconductivity and quantum superconducting circuits in Chapter 7. Justin Guttermuth who saved our asses when we had a house to move into, rooms to paint, a new baby, and I had this book to finish. My colleagues in the UMass Boston physics department for their support — especially Maxim Olchanyi, Bala Sundaram, Vanja Dunjco, and Steve Arnason. And last but not least, my wonderful wife Jacqueline, who helped me with the figures and the cover, and put up with the long hours this book required.