By the turn of this century the situation concerning logic was quite simple: there was basically one logic (classical logic) which could be used (by changing the set of proper axioms) in various situations. Logic was about pure reasoning. Brouwer’s criticism destroyed this dream of unity: classical logic was not suited for constructive features and therefore it lost its universality. Now by the end of the century we are faced with an incredible number of logics-some of them only named ‘logic’ by antiphrasis, some of them introduced on serious grounds.