In the generation following Copernicus, the question of planetary motions was picked up by two remarkable astronomers: Tycho Brahe and Johannes Kepler. Tycho was a Danish nobleman and brilliant astronomer and instrument builder whose high precision naked-eye measurements of the stars and planets were to be the summit of pre-telescopic astronomy. Kepler was the talented German mathematician who was hired by Tycho and succeeded him after his death who was to use Tycho's data to derive his three laws of planetary motion. These laws swept away the vast complex machinery of epicycles, and provide a geometric description of planetary motions that was to set the stage for their eventual physical explanation by Isaac Newton a generation later. Recorded 2007 Oct 10 in 1000 McPherson Lab on the Columbus campus of The Ohio State University.