Foster1654EllipticalHorologiographySamuel Foster, Elliptical, Or Azimuthal Horologiography (1654). This brilliant work, far ahead of its time, details Foster's development of analemmatic, circular, and diametral sundials and their generalizations. The title appeared earlier in compressed format as part of The Analemmatic Sundial Sourcebook – it is now available here as a separate volume within the Shadow Catcher Series.

This can be ordered from LuLu Books: Foster: Elliptical or Azimuthal Horologiography (1654)