Fred Bortz 
Johannes Kepler and the Three Laws of Planetary Motion [PDF ebook] 

Johannes Kepler is a fascinating man who would revolutionize humanity’s conception of the cosmos and their place within it. He would replace the Ptolemaic system with his three laws that described the orbital motion of the planets around the Sun. This scientist’s work continues to inform and facilitate modern advances in technology, astronomy, and astrophysics. In addition to being an enthralling life and times account of a great thinker, this biography also supports Common Core standards for the reading of biographies, historical and scientific accounts, the analyzing of the relationship between primary and secondary sources, and citing evidence to support that analysis.