Universal Logic: Frameworks and Structures.- From Consequence Operator to Universal Logic: A Survey of General Abstract Logic.- Abstract Model Theory as a Framework for Universal Logic.- A Topological Approach to Universal Logic: Model-Theoretical Abstract Logics.- Selfextensional Logics with Implication.- Logic without Self-Deductibility.- Identity and Nature of Logical Structures.- Equipollent Logical Systems.- What is a Logic?.- What is a Logic, and What is a Proof?.- Tools and Concepts for Universal Logic.- Non-deterministic Matrices and Modular Semantics of Rules.- Two’s Company: “The Humbug of Many Logical Values”.- Friendliness and Sympathy in Logic.- Logical Discrimination.