What do Leonardo da Vinci and Benjamin Franklin have in common with a grassroots activist, a citizen journalist, a civil rights lawyer turned drag queen, and a Wall Street VP by day, Grammy-winning musician by night? Each of these individuals is a master amateur. These days, self-taught innovators are rocketing past professionals in the race to define the future of work. Adaptable and resilient, these independent learners have mastered amateurism--the...