 Suggestions for Further Reading: For general discussion of The A theory and The B theory: Emery 2017; Le Poidevin 1998; Le Poidevin and McBeath 1993; Markosian 1993; Maudlin 2007 (especially Chapter 4); Mellor 1998; Paul 2010; Prior 1959 [1976], 1962 [1968], 1967, 1968, 1970, 1996; Sider 2001; Skow 2009; Smart 1963, 1949; Smith 1993; Sullivan 2012a; Williams 1951; Zimmerman 2005; Zwart 1976.