The Starry Messenger is Galileo's account of his first uses of his homemade telescope. He details his observations of the four newly discovered moons of Jupiter and several stars that can now be seen with the telescope. His Letters on Sunspots are a retort to another astronomer's theories on the nature of the phenomenon. In the Letter to the Grand Duchess Christina, Galileo puts up a staunch defense to the church in his adopting the Copernican heliocentric model of the universe. After being banned from teaching this opinion, Galileo makes a suave effort to communicate his ideas in a defense on the nature of comets in The Assayer.
This is the story of Galileo verses old dogma. One cannot help but sympathize with Galileo in his frustration in communicating what he believed to be true. In light of our current knowledge of the solar system and the logical arguments Galileo puts forth it is hard not to feel a bit of the same frustration. This book is a great treatise on Galileo's ideas and his tenacity in defending them. Galileo's Dialogue Concerning the Two Chief World Systems would be an excellent companion to this book. Drake has published a translation of this work also. Galileo's thoughts and observations mark a milestone in the history of astronomy, and Drake's book venerates the man and his teachings.