Galileo Galilei (1564-1642) was the first scientist in the modern use of the term. Instead of relying on the works of Aristotle, he actually carried out experiments to test theories legend has it that one of his experiments involved throwing weights off the Leaning Tower of Pisa. His astronomical observations with the telescope shattered the idea that the Earth was at the centre of the Universe, and led to his trial for heresy. He had a great lust for life, three children by a woman he never married, a biting, sarcastic with and the friendship of princes and (in spite of his run in with Pope Urban VIII) cardinals. An introduction, afterword and clear chronological table place Galileo s work in the context of the development of scientific knowledge.