This book is about “delta”, a paradox logic. In delta, a statement can be true yet false; an intermediate state, midway between being and non-being. Delta's imaginary value solves many paradoxes unsolvable in two-valued Boolean logic, including Russell's, Cantor's, Berry's and Zeno's.Delta has three parts: “inner delta logic”, covering “Kleenean logic”, which resolves self-reference; outer delta logic, covering Z mod 3, conjugate logics, cyclic distribution, and the voter's paradox; and “beyond delta logic”, covering four-valued logic and games.