Dialogue unfolds over four days, among three people. Salviati argues that Copernicus was right: The Earth orbits the Sun. Simplicio has an uncritical deference to Aristotle and Ptolemy. He's latched onto the idea that the sun orbits the Earth. Sagredo is the audience, an intelligent bystander.

This book inspires awe in the power of the human mind. Galileo wrote it more than one hundred years before flight (hot air balloons.) More than three hundred years before spaceflight (rockets.) Yet he's speculating about what the Earth looks like from space. And he's correct!

Galileo's deductions are admirable. He's deferential to evidence. He illustrates the dangers of accepting the word of authorities without question. The cornerstones of modern science, and, in part, the hacker way. Needless to say Galileo ended up in hot water with the authorities of his day, the Catholic Church.

This translation is easy to read. The margin summaries of what's happening during the dialog make it easy to skim back and forth.

If only everything was this lucid!