The implication operator (→) plays a significant role in the classical two-valued logic. Firstly, from the classical implication one can obtain all other basic logical connectives of the binary logic, viz., the binary operators - and (∧), or (∨) - and the unary negation operator (¬). Secondly, the implication operator holds the center stage in the inference mechanisms of any logic, like modus ponens, modus tollens, hypothetical syllogism in classical logic. © 2008 Springer-Verlag Berlin Heidelberg.