Public restrooms are problematic, and that’s not just because they may be dirty, inconveniently located, or lacking toilet paper. As co-editor Harvey Molotch points out, these places are inherently sites of ambiguity and unease because they provide a public setting for “intensely private acts.’’ Its very purpose makes the public bathroom into a theater in which issues of cleanliness, privacy, and gender play off questions of access, history, and culture. In “Toilet,’’ academics from the fields of sociology, law, urban planning, gender studies, archaeology, and architecture ponder the meaning of a room some people can’t even call by name (and whose polite name shifts by region, country, and social class).