Snow White is a sometimes impenetrably black fairy tale--comic, definitely, cosmic--maybe, by the talented young Mr. Barthelme whose short stories are familiar to New Yorker readers, earlier collected in Come Back Dr. Caligari. Well, Snow White lives with Kevin, Edward, Hubert, Henry, Clem, Dan and Bill (""seven of them only add up to two real men"") while waiting for her Prince (Valiant? Matchabelli? Philip?) and while they are washing buildings and making Chinese baby food, she's looking out the window. So were we, some of the time, until we came to the questionnaire at the end of Part I which is supremely funny but since we couldn't answer any of it, we've got one for him. Is it an intellectual legpull? A five finger exercise for amputees? An other-directed shell game? Pop art nouveau? A parable? A parody? or just piffle? Whatever, this is a startler, full of incongruous ideas, versatile wordsmanship and sudden surprise. In fact, it's a Happening, a happy Happening.