This Element presents the basic principles and motivations of Meinongianism, both in its historical and contemporary versions.

Meinongianism (named after Alexius Meinong) is, roughly, the view that there are not only existent but also nonexistent objects. In this book, Meinong's so-called object theory as well as “neo-Meinongian” reconstructions are presented and discussed, especially with respect to logical issues, both from a historical and a systematic perspective. Among others, the following topics are addressed: basic principles and motivations for Meinongianism; the distinction between “there is” (“x”) and “exists” (“E!”); interpretations and kinds of quantification; Meinongianism, the principle of excluded middle and the principle of non-contradiction; the nuclear-extranuclear distinction and modes of predication; varieties of neo-Meinongianism and Meinongian logics.