Part I. Ontology -- Existence (1987) -- Nonexistence (1998) -- Mythical objects (2002) -- Part II. Necessity -- modal logic Kalish-and-Montague style (1994u) -- Impossible Worlds (1984) -- An empire of thin air (1988) -- The logic of what might have been (1989) -- Part III. Identity -- The fact that X=Y (1987) -- This side of paradox (1993) -- Identity facts (2002) -- Personal identity : what's the problem? (1995u) -- Part IV. Philosophy of mathematics -- Wholes, parts, and numbers (1997) -- The limits of human mathematics (2001) -- Part V. Theory of meaning and reference -- On content (1992) -- On designating (1997u) -- A problem in the Frege-Church theory of sense and denotation (1993) -- The very possibility of language (2001) -- Tense and intension (2003) -- Pronouns as variables (2005).