Ayan S. Mandal, PhD, is a neuroscientist at the Perelman School of Medicine at the University of Pennsylvania. Prior to attending medical school, he received the Gates Cambridge Scholarship to pursue a PhD at the University of Cambridge. His thesis was on the neuroscience behind how tumors spread within the brain. In medical school, he was fascinated to learn the myriad ways doctors diagnose and treat patients before they get sick. To outline the search for proactive strategies to treat brain diseases, he wrote his first book, A Stethoscope for the Brain.