This is a far-ranging and impeccably researched book focused on Christmas, but touching on many other topics, including separation of church and state, economics, history of religion, language, and sociology. Parts of it were detailed rehashes of information I'd read many times before, but parts were quite new to me and interesting. The chapter on the origins of the Santa Claus myth was particularly informative; the author makes the case that Santa Claus is not at all based on St Nicholas.
The author claims initially that the book will end with advice about "taking back" Christmas, and I was dreading what that might amount to. I was pleased to see it was more along the lines of do what you want, don't tell others what to do, and consider not telling kids that Santa is literally real. I don't wish to "take back" Christmas, I find the holiday dreadful, and I wish there were more encouragement in the book for just dropping the holiday altogether, rather than transforming it.
I also wish the author were not quite so gentle with religion, most notably in the Santa chapters. I do think the Santa myth is very much like the God myth, I don't see any substantive difference in the preposterousness of either, and I know of a number of people who have become atheists through analogy with Santa. That's good, that's critical thinking. Maybe the parents who are worried that learning Santa is fiction might lead their kids to question God should give some thought to their own beliefs.