Between 1623 and 1634, Galileo Galilei’s daughter, Sister Maria Celeste (born Virginia in 1600), wrote him more than 120 letters. In 1999, Deva Sobel translated these letters into English as the basis for her book, Galileo’s Daughter. This site, part of the larger Galileo Project , provides searchable transcriptions of more than 100 letters. Though no return correspondence from Galileo is included, Maria Celeste’s letters illuminate their close relationship. The letters simultaneously provide insight into Galileo’s life and work—his important scientific discoveries and inventions in physics and astronomy, and his time in the Medici court in Florence—and shed light on his daily activities. The letters also help recreate Maria Celeste’s personality and thus illustrate women’s roles at the time of the Italian Renaissance. The rest of the Galileo Project consists of secondary-source text written by Albert Van Helden, Professor of History at Rice University, about Galileo and his contemporaries, and on the Medici court, Christianity, scientists, and scientific advancements. A few additional primary-source resources can be found in the “Portraits” section, which includes 10 portraits of Galileo, and about 10 pictures each of other scientists and Galileo’s contemporaries. For further information on Galileo’s scientific life see Galileo Galilei’s Notes on Motion, which provides more than 300 page images of the manuscript that led to Galileo’s publication of Discorsi.