Hadronic interaction phenomenology, heavy ions, Bose-Einstein and all that

I survey some features of our knowledge of the hadronic interactions and their implications on the model building with applications to heavy ion reactions. Finally I present a model for Bose-Einstein correlations which at present is applied to the Fritiof model and at least in e+e--annihilation reactions imply 'intermittency' in the sense of factorial moment growth in small rapidity intervals. (orig.)