This the logical area of my homepage. In this growing section all sorts of useful things will come.
There is not one logic there are many logics. A logic is a reasoning system. Some logics are general and can be used for various purposes e.g. propositional and predicate logic. Other logics function as an extension of other logics e.g. modal, deontic, temporal logic. Other logics are there to solve specific problems e.g. paraconsistent logics to solve problems with various paradoxes e.g. the liar paradox.