Definitely the geekiest book I’ve purchased in a while:
It provides calculations and software algorithms for a lot of different calendar systems, both modern and not-so-modern. Description in the preface.
I will probably get very little use out of this in practice, but I’ve been working with the authors’ calendar/lunar/holiday libraries in Emacs recently, and learned about the existence of the book as a consequence, and more or less ordered it on a whim. It’s larger than I was expecting :).
I showed it to a colleague at work, who replied:
“The subsequent addition—by popular demand—of the Mayan and French Revolutionary calendars to GNU Emacs…”
This says a lot about the Emacs community :).
