http://arxiv.org/abs/astro-ph/0505267 Lorentz violation at high energy: concepts, phenomena and astrophysical constraints Ted Jacobson, Stefano Liberati, David Mattingly 56 pages, 3 figures, Invited article for Annals of Physics "We consider here the possibility of quantum gravity induced violation of Lorentz symmetry (LV). Even if suppressed by the inverse Planck mass such LV can be tested by current experiments and astrophysical observations. We review the effective field theory approach to describing LV, the issue of naturalness, and many phenomena characteristic of LV. We discuss some of the current observational bounds on LV, focusing mostly on those from high energy astrophysics in the QED sector at order E/M_Planck. In this context we present a number of new results which include the explicit computation of rates of the most relevant LV processes, the derivation of a new photon decay constraint, and modification of previous constraints taking proper account of the helicity dependence of the LV parameters implied by effective field theory." Ted Jacobson et al are the recognized world-class experts on testing for tiny deviations from c at the high end----which may become detectable over cosmological distances. This is an invited article describing the current status of efforts to test for Lorentz violation. If DSR gets shot down, the chances are Jacobson Liberati Mattingly will be on hand, likewise if it is confirmed. IMO this will not become interesting until around 2007, but this survey article can serve to keep us aware of what to expect.