Highlights of the reaction. pi. /sup -/p. --> pi. /sup -/. pi. /sup +/n at 100 and 175 GeV/c

We present a summary of the physics results from an experimental study of the reaction ..pi../sup -/p..--> pi../sup -/..pi../sup +/n at 100 and 175 GeV/c incident-beam momentum. Our data show the continuing dominance of one-pion exchange in these reactions with the characteristic 1/p/sub tab/ /sup 2/ momentum dependence. We extract the pion Regge trajectory from our data on ..pi../sup -/p..-->..rho/sup 0/n and study the zero structure of the ..pi pi.. differential cross section up to s/sub pipi/ = 12 GeV/sup 2/.