When in their lives are innovators most creative, and why? This book summarizes more than two decades of research prompted by this question. The result is an authoritative statement of a new unified theory of creativity, that overturns both popular and scholarly beliefs about the sources of human inventiveness. David Galenson shows that there are two distinctly different kinds of creativity in virtually every discipline. They result from very different goals and methods, and each produces a specific pattern of discovery over the life cycle. Conceptual innovators make bold leaps to formulate new ideas. The most radical conceptual innovations are made by brash young geniuses, who often lose their creativity thereafter. Great conceptual innovators analyzed in this book include Pablo Picasso, Albert Einstein, Orson Welles, Sylvia Plath, Andy Warhol, Bob Dylan, and Steve Jobs. Experimental innovators make discoveries gradually and unobtrusively, through careful observation and generalization. They gain knowledge over time, and make their greatest contributions late in their lives. Great experimental innovators considered in this book include Paul Cezanne, Charles Darwin, Virginia Woolf, Robert Frost, Alfed Hitchcock, John Coltrane, and Warren Buffett. From analysis of the careers of scores of artists, scholars, and entrepreneurs, this book provides a new understanding of the creative processes of great innovators, and reveals the systematic patterns that underlie the two life cycles of creativity. It will be of interest to anyone who seeks a deeper understanding of the sources of human creativity.