After a life of intellectual prosperity against all the prevailing norms of her time, her life was tragically cut short after finishing her greatest work, the only complete French translation and annotation of Newton's Principia Mathematica to this day.

[T]o her dismay, Du Châtelet discovered that she was pregnant. Then aged 43, she was an elderly women by contemporary standards. Although Voltaire was not the father, he helped Du Châtelet deceive her husband into thinking that the baby was legitimate. Plagued by gloomy premonitions, Du Châtelet intensified her work schedule, working 18 hours a day to finish in time. Although she did succeed, she died soon after the baby was born. On her last day she recorded the date on her Newton commentary. Her Principia was published 10 years later, in 1759, to coincide with the return of a comet vindicating Newton's physics.

David Bodanis has written a new book about Voltaire and his one-of-a-kind relationship with Ms. Du Châtelet. A great interview with the author.