There have been a great many books about Galileo in recent years, starting with Dava Sobel's Galileo's Daughter. What makes this book different is that it ties Galileo's earliest discoveries to what modern science knows about the Universe today. Co-authors Stephen Maran and Lawrence Marschall are well equipped to tell this story, with Maran having spent 35 year with NASA and Marschall having taught astronomy, physics, and science writing for many years as well.
The book is organized around a series of topics dealing with the instruments and the objects of astronomy. Chapter one gives us a brief summary of Galileo's life, and the age in which he lived. Chapter two deals with telescope, and succeeding chapters start with Earth's Moon, and from there, take us to the Sun, the planets, and beyond. Each chapter tells two stories: First, what was known about the topic in the ages of Galileo, and what Galileo added to that knowledge, and second, what science has discovered since then. This narrative style does an excellent job of illustrating Galileo's place in the historical narrative of astronomy, and helps the reader to better understand how pivotal Galileo's role was in explaining the Universe around us.
If this book has one fault, it's the lack of illustrations. It's very difficult to explain how a telescope works, or the arrangement of the planets, with text alone- particularly for the reader unfamiliar with astronomy. I think this book would be greatly improved with the addition of simple line drawings and star charts, and I would encourage the publishers to consider doing this in future editions.