Through engaging storytelling and historical, biographical, and scientific research, Spark unravels the relationship between brains, talent, passion, creativity, willpower, and imagination. Spotlighting 13 icons past and present, Kalb explores how—and when—inspiration strikes among high achievers in the arts, politics, business and science. The chapters in Spark are organized not by birth order but by the age at which genius ignites. Child prodigies Pablo Picasso, Shirley Temple, and Yo-Yo Ma launch the book, followed by Bill Gates, Isaac Newton, and entrepreneur Sara Blakely, whose moments of discovery span the ages of 13 to 27. Julia Child, Maya Angelou, and Alexander Fleming constitute the midlifers—people whose momentous experiences transpired in their 30s and 40s. The chapters close with late bloomers Eleanor Roosevelt, Peter Mark Roget of Roget’s Thesaurus fame, and Grandma Moses, all of whom initiated their most enduring work in the final decades of their lives. In the book’s final pages, Kalb pays tribute to Leonardo da Vinci, a transformative genius whose intellect and artistry illuminated every stage of his life.