Age: 40
Occupation: Physician, author
Previous TIME 100 appearances: 0
His academic pedigree is impressive enough — a Stanford B.A., a Rhodes scholarship and a Harvard M.D. — but Mukherjee wasn't satisfied with simply studying and treating cancer. He wanted to understand this disease that has stalked the human race for at least 4,000 years, to appreciate its likes and dislikes, its bursts of pathologic activity and its periods of seeming biological fallowness. Setting out to write nothing less than a biography of cancer, Mukherjee produced a groundbreaking book, The Emperor of All Maladies, that will forever give patients — and their doctors — an answer to the question, What is cancer?