Questioning established knowledge isn't usually a popular course of action. Galileo learned this throughout his life as he tested scientific theories using mathematical calculations. He challenged the Catholic Church and Aristotle, which got him into trouble, but also added him to the pantheon of great scientists. Readers learn all about Galileo's most important discoveries through the story of his life, complete with historical images. Sidebars add detail and understandable explanations to the main content, including concepts such as the scientific method and the planets orbiting the sun.