What happens to the spark of greatness many 18-year-olds have when they arrive at MIT, Harvard, Caltech or Stanford? For most, Edwin Land once said, it is extinguished by undergraduate education's preoccupation with "questions to which the answers are known." The message in all those lectures and exams, he feared, is that the "secret dream of greatness is a pipe-dream; that it will be a long time before [a student] makes a significant contribution-if ever."

Land's unwillingness to wait helps explain why he dropped out of Harvard (twice) and, at the age of 24, earned the first of his 535 U.S. patents on the manipulation of light. It may also explain his interest in instant cameras, born one day in 1943 when his equally impatient young daughter, whose picture he had just taken, asked why she could not see it right away. What is certain is that Land's irreverence toward received wisdom helped him to build a unique empire of invention, the Polaroid Corp., and to transform the way his contemporaries thought about not one, but three momentous subjects: photography, nuclear-age military reconnaissance and the biology of color vision.