**Glen Van Brummelen *is dean of the faculty of natural and applied sciences at Trinity Western University, and a historian of mathematics and astronomy. His many books include The Mathematics of the Heavens and the Earth: The Early History of Trigonometry and Heavenly Mathematics: The Forgotten Art...

**Glen Van Brummelen *is dean of the faculty of natural and applied sciences at Trinity Western University, and a historian of mathematics and astronomy. His many books include The Mathematics of the Heavens and the Earth: The Early History of Trigonometry and Heavenly Mathematics: The Forgotten Art of Spherical Trigonometry * (both Princeton).