  In this talk we cover several issues concerning pion production. The first
one is the p p ----> p p pi^0 reaction where an alternative explanation based
on the off shell extrapolation of the pi N amplitude is offered. A recent model
for the gamma N ----> pi pi N reaction is presented and a new kind of exchange
current is constructed from it which allows one to address problems like double
Delta photoproduction from the deuteron. Finally the (gamma, pi pi) reaction in
nuclei is studied and shown to be highly sensitive to the renormalization of
the pions in nuclei.

High Energy Physics - Phenomenology;Nuclear Theory