For nearly 50 years, chemical engineer and inventor Mária Telkes applied her prodigious intellect to harnessing the power of the sun. She designed and built the world’s first successfully solar-heated modern residence and identified a promising new chemical that, for the first time, could store solar heat like a battery. And yet, along the way, she was undercut and thwarted by her boss and colleagues — all men — at MIT. Despite these obstacles, Telkes persevered and, upon her death in 1995, held more than 20 patents. She is now recognized as a visionary pioneer in the field of sustainable energy. An unexpected and largely forgotten heroine, Telkes was remarkable in her vision and tenacity — a scientist and a woman in every way ahead of her time. Her research and innovations from the 1930s through the ‘70s continue to shape how we power our lives today.