"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 "A guided tour through the museum of mathematics. . . . [ The Doctrine of Triangles] takes the history of trigonometry, which is a formidable subject in its scope and size, and transforms it into something readable."---Daniel Mansfield, The Mathematical Intelligencer "Very easy to read, and there are lots of helpful diagrams, especially for the spherical trigonometry . . . [ The Doctrine of Triangles] is deeply enriched by extracts from contemporary texts, given first in fairly literal English translations, often accompanied by the original diagrams, and then explained in modern terms. So mathematical readers (and, I hope, their students) can experience a little of what trigonometry was actually like at each stage in its history."---John Hannah, Aestimatio