I have never been completely convinced by the revisionist story that one often gets (including from such unlikely quarters as Thomas Henry Huxley) that Galileo basically brought his condemnation by the Inquisition on himself. The story is a complex one and tends to get told as one of patronage politics gone wrong. Sobel, rightly in my view, brings us back to the scientific truth of Galileo's observations; and whatever the reasoning and motives for Pope Urban VIII's pursuit of him, the fact remains that the ecclesiastical authorities were given all the right information and came up with the wrong answer, and while Sobel doesn't rub it in, she doesn't veer from the central point either.
The central point is not, in fact, Galileo's daughter; the title of the book is misleading. Galileo's life is very charmingly illustrated by the letters he received from his daughter Sister Maria Celeste, born in 1600, over the period from 1623 to her early death in 1634, which of course cover the key moments of his own career. I shall always now think of him gardening in his leather jacket. But I think Sobel misses an opportunity to reflect on the life prospects of women like Galileo's daughters, immured in the Poor Clares convent in their early teens - and their mother, who bore the scientist three children before marrying someone else. It is a necessary but absent piece of context.
Still, the book is a very good example of how to take a particular motherlode of primary source material and weave a good story around it.