In chapter 10, Mr. Jennings does a great job summarizing the history of geocaching, and provides some very interesting insights through interviews with Dave Ulmer (hider of the very first "geo-stash"), Jeremy Irish, along with top-cachers; EMC of Northridge CA, and Alamogul. It includes some interesting tidbits about how Ulmer was not a fan of geocaching.com at all for many years, and a discussion of what might have prompted the world's most prolific cacher at the time, CCCooperAgency, to suddenly just walk away from the sport in 2009, never to cache again.
So if you are a fan of maps and cartography, you will really enjoy this book. And, if you also enjoy geocaching (and who doesn't?), then you'll love this book; especially chapter 10.
Maphead is available on Amazon: Maphead: Charting the Wide, Weird World of Geography Wonks