To my publisher Phillipa McGuinness, thank you for the opportunity to make this book a reality. I always left our lunch meetings confident and inspired to continue, and I have greatly valued your warm and inspiring mentorship throughout this journey. To Emma Driver, copyeditor extraordinaire, your thought-provoking queries and efficiency made the process fun. To the late Oliver Sacks, whose books inspired me to become a clinical neuropsychologist and to write a book myself. To my PhD supervisors Sarah Wilson, David Reutens and Peter Bladin, thank you for introducing me to this fascinating topic and for facilitating my PhD, which was the seed of this book. To my interviewees Till Amelung, John Christie, David Ley, Nicole Prause, Brian Russman and Vanessa Thompson, thank you for your time and insights, which made an important contribution to this book, and thanks to Justin Lehmiller and Adrian Carter for pointing me in the direction of relevant literature for Chapters 9 and 10 respectively. To George, thank you for your friendship and for allowing me to discuss your life. To my late father, Rob, who no doubt had an influence on my drive to understand the brain. To my parents Gabriele and Drew, your love and endless encouragement to pursue my dreams have enabled me to do just that. Thank you to my husband, Tim, for your calm patience in listening to me talk about this book and my career fantasies over the years, and for letting me disappear for hours on weekends to write. To my children Louis, Clara and Theo, I hope that once you are old enough to read this book you will understand why I was so excited to write it. Finally, to my patients, thank you for your candid discussions about the intimate details of your life. It is a privilege to have met you.