Growing up, Thanksgivings in Jennet Conant’s house were contentious. The Vietnam War was raging, and in Cambridge, Massachusetts, student protests were ubiquitous. But Conant’s family was especially combative. Her grandfather, James B. Conant, a former president of Harvard University, had both supervised the production of poison gas during World War I, and oversaw the development of the atomic bomb during World War II.

Conant’s father argued her grandfather wasn’t a scientist who had served his country, but a mass murderer.

Jennet Conant is the author of a new biography of her grandfather, “Man of the House: James B. Conant, Warrior Scientist,” as well other books about war, science, and the intersection of the two. She explains what happens when people use science to create weapons - and the fallout for the scientists themselves.