Galileo Galilei is famous for many things: for his science (Einstein called him the "father of modern physics"); for his flamboyant style (he wrote in Italian not Latin, enlivened texts with rough humour, argued loudly in staged debates) and for his harsh treatment by the Catholic Church. What"s less well known are the details of his private life--a life that, as Dava Sobel points out in Galileo"s Daughter, was just as complex as the scientist"s public life. Galileo had three illegitimate children; the book"s title refers to the oldest, Virginia, later Suor Maria Celeste (she took the name in acknowledgement of her father"s fascination with the stars). Unable to marry because of her illegitimate status, Virginia entered a convent at 13 and maintained a lifelong correspondence with her father. Sobel has translated Virginia"s surviving letters for the first time and, combining those letters, commentary, and gorgeous illustrations, she sets out in Galileo"s Daughter to illuminate a different side of Galileo, the father deeply committed to his daughter and to her faith. Virginia"s letters are tender, witty and intelligent. They are crammed with details of day-to-day life in Florence: "The broad beans are set out to dry and their stalks fed for breakfast to the little mule, who has become so haughty that she refuses to carry anyone." Sobel"s commentaries brilliantly help to put into contextual the letters. "Most of Suor Maria Celeste"s letters travelled in the pocket of a messenger or in a basket laden with laundry, sweetmeats or herbal medicines." But life in the convent was not idyllic. Virginia was surrounded by women in various states of mental collapse and her letters describing those collapses are vivid and at times terrifying. The bubonic plague, too, affected the nuns just as it did the outside world. But what emerges most strikingly from these letters is the degree to which Virginia supported her father. Suor Maria Celeste may never have left the convent but in her letters she accompanies her father through physical and intellectual trials. We see her planning her brother"s wedding (which she can"t attend) and copying out her father"s manuscripts. The relationship between father and daughter "is not a tale of abuse or rejection or intentional stifling of abilities", writes Sobel. "Rather, it is a love story, a tragedy and a mystery." --Simon Ings