Ever since Galileo Galilei suddenly emerged from obscurity in the early 17th century, he has fascinated scholars and biographers, playwrights, poets and popes. Marjorie Nicolson, in her classic book "Science and Imagination," put her finger on one of the reasons for that continuing preoccupation: "We may perhaps date the beginning of modern thought from the night of January 7, 1610 when Galileo, by means of the instrument he had developed [the telescope], thought he perceived new planets, and new, expanded worlds." Galileo's discovery of the moons orbiting Jupiter, and his many other celestial observations, threatened the current cosmology, drawn as much from the Aristotelians as from the Bible, by which all motions in the heavens were thought to be centered on a fixed Earth, the unique focus of God's attention and favor. Galileo's findings, by which he signaled his adherence to the planetary system Copernicus had put forward in 1543, led to a whole catalog of what an initial minority regarded as triumphs of reason and experiment, but what the majority felt to be intolerable assaults on their self-confidence and on the revered ancient teachers' well-tuned and comfortable worldview. Mankind, with reduced significance, seemed by these new challenges to be decentered and launched into the unfathomable Copernican void, causing John Donne's famous outburst of 1611, "Its all in peaces, all cohaerence gone." Through the publication of that scientist and his followers, the list of culture shocks grew exponentially: the elevation of the mathematical aspects of nature over the qualitative ones; the experimental over the intuitive; the objective and skeptical over the subjective and mystical; the divorce of the natural from the supernatural; and with Newton, who acknowledged his debt to Galileo, the mechanization of the universe. As the great scholar Alexandre Koyre remarked: "The mighty, energetic God of Newton who actually 'ran' the universe according to His free will and decision, became, in quick succession, a conservative power, an intelligentia supra-mundana, a 'Dieu faineant'. . . . The infinite Universe of the New Cosmology . . . inherited all the ontological attributes of Divinity. Yet only those--all the others the departed God took away with Him." The change from the Aristotelian to the Galilean view of how nature works was, as Steven Weinberg explained in his important essay, "The Revolution that Didn't Happen" (published a year ago in the New York Review of Books), the only major transition in the history of scientific thought that truly deserves the name "paradigm shift." Standing on the watershed between ancient and modern science, Galileo, in his writings and through his fate, has continued to raise a variety of fundamental questions that persist to this day. Some examples: If God can be known through the scriptures, can He also be apprehended through science? Or are the findings of science and the dogma of religion doomed to be antagonists? How much "evidence" is needed to make a scientific revolution in the first place? What happens when such a major change is proposed, both to the originator and to society itself? What lessons for today may be drawn from the story of the political-ideological battle waged by well-armed enthusiasts against a major scientist or scientific theory? These are among the timely problems skillfully woven into the new biography of Galileo by Dava Sobel, also the author of the fascinating book, "Longitude." Her "Galileo's Daughter" is a gripping story, whose main characters are the brilliant but doomed scientist, his adoring and ingenious daughter, Virginia, and the extraordinarily zealous Pope Urban VIII. While the events cover the span of Galileo's life from 1564 to 1642, some of them seem strangely familiar from the latest news stories emerging from, say, a current inquisitor in Washington or a school board in Kansas.