I actually finished the book on Wednesday, but I've been busy which is why you're only getting a review now.
Let me start by briefly outlining the author's project: he wants to show the audience the ways that the concept and time of "Night" was treated differently in the early modern western world than it is now, and he uses a number of resources, most of them drawn from individual accounts, to show this difference.
Unfortunately, he doesn't do that as well as he could: one of the most stunning revelations he presents is that most people in the premodern era did not sleep in one continuous block of time as we do now. I think putting that in the first chapter or so would have gone a long way towards establishing the sense that night was different than it is today, and been a good hook to carry us along on his examination of nocturnal activities. Instead, it's in the second-to-last chapter, by which point it amounts to little more than an anecdote.
Another problem with the book is that he wants to separate different topics into different chapters or sections(ie "work at night", "night & magic"), and the subject matter doesn't always lend itself well to that kind of separation: certain kinds of activities with different motives were carried out in concert or conflict at night, and because they were described in different sections it was annoying having to flip back and forth to look for details.
A last limitation of the book is that the author is painting in very broad strokes, and while he present anecdotes from various places and times, he doesn't do a good job of showing the evolution of night within the period, or of establishing any regional differences. This isn't necessarily always a bad thing, but there are some times where I wish the book would focus more than presenting me with everything between Berlin and Baltimore.
After all this griping, I still liked the book.
He does a good job presenting some of his themes, especially the co-mingled issues of personal freedom and danger. The anecdotes are drawn from people both great and small, and often do a good job of filling out his narrative. I'm a sucker for the early modern period of western civilization, so histories of those centuries are quite an easy sell to me.
And, he identified the night watchman as humanity's oldest profession, rather than the prostitute. And that was something that I realized in the course of my own many nights up watching silent buildings, and therefore earned him a bunch of points with me.
Alright, time for me to get some sleep of my own, and I hope you all can do the same.