The Sun in the Church: Cathedrals as Solar Observatories Book

This book was recommended to me by a science historian, and is unusual in that it is both a history book and a science book.
As an account of history, it is magnificent. Thoroughly well-researched, with a comprehensive cast of characters, Heilbron succeeds in bringing the seventeenth and eighteenth centuries to life, with all the political and religious aspects surrounding accurate calendaring, developing astronomical methods and controversial (Copernican) ideas. The Cassini family played a central role in the narration, and it was especially interesting to learn of the genius of Gian Domenico Cassini.
As a science book, it is also wonderful. The book is replete with astronomical tables and geometrical diagrams illustrating important points at the cutting edge of astronomy at the time. Descriptions of the meridian lines built in several cathedrals around Italy and France during this time period form the majority of the book, with in depth analysis of the various challenges each one faced along with their benefits and contributions to science.
The interweaving of historical narration with mathematical geometry tends to break the flow of the book a little, but the decision to include mathematics in the book, while perhaps restricting the potential readership, was ultimately a good one, making it stand out in a genre where equations are often shunned in favor of descriptive analogies.