When Doug Melton, one of the premier stem cell scientists in the world, found out his son had Type 1 diabetes, he transitioned from basic research to a search for a cure.

Dr. Anne Goldfeld does the work of three people: fighting for human rights, treating seriously ill patients in Cambodia and Ethiopia, and conducting research to help eradicate AIDS and tuberculosis.

Zipcar founder Robin Chase believes that collaboration is essential to solving the world’s most pressing problems.

Dr. Jim O’Connell has made Boston a model for how to provide health care to the homeless, and his approach is now a template for similar programs around the world.

Russell Wilcox co-founded E Ink, the company that took a new technology out of MIT to create and build e-reader screens. Now he’s taken the helm of another start-up out of MIT with the goal of powering the world on nuclear waste alone.

Since the late 1990s, Cambridge author M.T. Anderson has been crafting smart, often dark books for teens that also draw adult readers.

From a teenage appearance on the “Tonight Show” to a 2012 Grammy Award, Terri Lyne Carrington remains a role model not just for drummers, but for aspiring female musicians everywhere.

Over four decades, Clara and Bill Wainwright have nurtured countless creative collaborations in Boston while making their own work and overcoming some major obstacles.

We begin a new series, “Visionaries,” by profiling the tech-driven, inventive composer Tod Machover.