Johannes Kepler and the Music of the Spheres
- An article by David Plant describing Kepler's astrological beliefs.
- http://www.skyscript.co.uk/kepler.html

Starry Messenger: Johannes Kepler
- Biography, and information on Kepler's mathematical techniques, poetry, and interest in astrology. From the Whipple Museum of the History of Science.
- http://www.hps.cam.ac.uk/starry/kepler.html

Johannes Kepler
- Includes detailed biography, online links, outlines of some of his works, quotes, and reading list.
- http://www.johanneskepler.com

Astronomy History - Johannes Kepler
- Brief biography highlighting his status as a defender of Copernicus and a formulator of planetary-motion laws.
- http://space.about.com/library/weekly/aa090702a.htm

Tycho Brahe and Johannes Kepler
- Short biographies.
- http://galileoandeinstein.physics.virginia.edu/lectures/tycho.htm

More Kepler, by Michael Fowler
- Part two of a biography, discussing Kepler's investigations of planetary motion and gravity.
- http://galileoandeinstein.physics.virginia.edu/1995/lectures/morekepl.html