Neither of these are in English but the image reproductions are valuable and focus on especially early erotic photography, daguerreotypes mostly.

Die erotische Daguerreotypie Sammlung Uwe Scheid

and

Le Nu Stereoscopique

There were virtually no erotic daguerreotypes produced in the US or Britain, nearly all were French, as a result most books on the subject are not in English. But any in-depth book covering daguerrean art in France should touch on the subject and general history.