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).
Glen van Brummelen has prepared a highly recommended, accessible and definitive history of the subject that will serve as a resource for scholars for decades to come. ---Daniel Otero, MAA Reviews The Doctrine of Triangles is an informative and valuable reference work. ---Wallace A Ferguson, Institute of Mathematics and its Applications