Edited in collaboration with FoLLI, the Association of Logic, Language and Information, this book constitutes the 5th volume of the FoLLI LNAI subline. It contains the refereed proceedings of the Third Indian Conference on Logic and Its Applications, ICLA 2009, held in Chennai, India, in January 2009.

The 12 revised full papers presented together with 7 invited lectures were carefully reviewed and selected from numerous submissions. The papers present current research in all aspects of formal logic. They address in detail: algebraic logic and set theory, combinatorics and philosophical logic, modal logics with applications to computer science and game theory, and connections between ancient logic systems and modern systems.