Lots of interesting facts, with a slightly clunking interpretational frame and style. Mr. Koslofsky has been reasonably well trained in grad-school prose and thinking - enough that he is probably safe from any career-threatening denunciations of 'feuilltonism', but not so well that he is so unpleasant as to be unreadable. I suspect that Tim Blanning probably got it right in his review with his magnificent (in the old-fashioned sense) observation that a major virtue of the book is the amount of empirical stuff it delivers as support for the not terribly empirically outfitted Strukturwandel der Öffentlichkeit - I suspect, but I can't actually be sure, since I still haven't read the copy of the latter I acquired five years ago. I suppose I should, now.
As far as interpretation goes, all the usual foucauldian suspects are here: power, gender, race, etc., The only one that flows naturally from the material is probably power/control but it, together with the development of sociability, is more than enough. Also, for me, there was too little discussion of the economic and technological developments that drove what Koslofsky calls 'Nocturnalisation' (there is some cursory discussion of street lamp technology, but nothing deep and nothing about economic drivers - culture just happened - but really culture doesn't just happen - people had more photons to play with, and I wanted to know in more detail how and why), and things do get a bit fuzzy in the final chapter's discussion of (radical) enlightenment culture, which seems to be straining very hard to say something - anything - and not really succeeding (what I really wanted to know was what time dinner was served chez Paul d'Holbach; but that - actually somewhat important - fact is not provided*).
Anyway, if you are already interested in early modern European cultural history, this is definitely worth a look.
P.S., Oh yeah, and somebody could, in fact really should, have advised against the triumphant final citation, in the final paragraph, of something called - and I kid you not - 'Cultures of Darkness: Night Travels in the Histories of Transgression'. It doesn't help!
P.P.S. The most interesting, not to mention unnerving, fact of all, however, is that on the 'customers who bought this' list on the page for this, I count seven books that I own.
* [14/2/2012: Ha! Dinner started at 2 in the afternoon, and continued often until 7 or 8 - Andre Morellet]