A lot. Could you be more specific as to any geographical or chronological preferences? Are you looking towards more theoretical/methodological approaches, for general overarching (i.e. often Western-centric) narratives, for specific areas, or for an entire global introduction?

There are simply too many possibilities to list here without further specification. For instance, you could go through each individual era and piece a historical patchwork throughout the times yourself, through McGinn on The Economy of Prostitution in the Roman World, Otis on Prostitution in Medieval Society (Languedoc) and Karras on Common Women (medieval England), Walkowitz on Prostitution and Victorian Society (19th-C England), Frances on Selling Sex (Australia), Kushner's Erotic Exchanges (elite prostitutes in 18th-C Paris), and these are just some arbirtrary examples of more recent books, to skip the hundreds (quite likely thousands) of articles published in the past three to four decades on prostitution in European history. (See Gilfoyle's 1999 review in the AHR on how post-70s interest in this had already created a trend by the end of the 90s: http://www.jstor.org/discover/10.2307/2650183.)

I haven't recommended any particular works since, as I've stressed, it's hard to know what you'd like exactly, and none of the above excepting Gilfoyle's include any articles, which is only since they're ordinarily pay-walled, and then even more specific than monographs. If you'd like a taster, however, see e.g. Kushner's article for Slate (http://www.slate.com/articles/news_and_politics/history/2014/04/elite_prostitutes_in_18th_century_paris_and_the_detectives_who_watched_their.single.html) that adapted passages from her work.