 The Republic is central to Plato’s ethical and political thought, so some of the best discussions of it are contained in more general studies of Platonic ethics and politics. See especially Annas 1999, Bobonich 2002, Irwin 1995, Klosko 2007, Mackenzie 1986, Monoson 2000, Pradeau 2002, Samaras 2002, Schofield 2006, and Vasiliou 2008, and the relevant essays collected in Benson 2006 and Fine 2008.  