Calendar

This book focuses mainly on the calendar of that the Western world uses, and how it came into being. It does touch on various other calendars (Hebrew, Mayan, etc.) but does not explore these in depth. There is a good amount of math, which I found myself either going over several times to try and understand or skimming over in order to maintain focused on the story. Don't let this stop you though, because the book is really very interesting and quite well written.