The 2010 TIME 100

In his best-selling book The Checklist Manifesto, Atul Gawande, 44, makes a compelling case for using simple checklists in medicine and other fields. Here are the two reasons Gawande is one of the most influential healers in the world.

First: Making a lasting contribution to society and to a profession. Gawande once said, "It turns out you can be a doctor and be almost anything else." That realization led him to become a researcher, a practicing physician, a Harvard professor, a lecturer, an author and a senior adviser to President Bill Clinton. His studies on surgical procedures and health costs as well as his advocacy for reform have had a profound impact on medicine and policy. The new health-reform law has Gawande's fingerprints all over it. Check.

Second: The likelihood of similar future impact. In this historic time for health policy, the need for smart, creative thinkers is greater than ever. Gawande certainly is one — and it is equally certain his influence will grow. Check.

Daschle, a former Senator from South Dakota, is a senior adviser for DLA Piper

TIME 100 Social-Networking Index: 1,190