The Crystal Ballroom by Libby Sommer Ginninderra Press, 2017, 158 pages, $25 ____________________________ Have you ever heard Latin American music coming from an upper room over a shop, and lingered briefly at the sign about dancing classes? Perhaps you have seen people—a man in built-up shoes or a woman with a surfeit of silver bangles—heading for an old town hall after dark. The world of ballroom dancing and tango lessons has its own etiquette and hierarchies. Libby Sommer’s new fiction, The Crystal Ballroom, lifts the lid on the delights and pitfalls of this fascinating sub-culture. In elegant, pared-down prose, Sommer’s…