Light by light scattering at a low energy e^+e^- collider -or- What to do while waiting for that rare kaon decay event

Two photon processes are a wonderful by-product of an $e^+e^-$ collider at any energy. Two photon reactions probe the very structure of matter. A machine operating below 2 GeV has the potential to reveal the Higgs sector of the strong interaction -- the scalars with vacuum quantum numbers that reflect dynamical mass generation from the breakdown of chiral symmetry. One of the many $e^+e^-$ machines around the globe must have a dedicated $\gamma\gamma$ facility.