Abstract: | There is now good evidence for astronomical sources of gamma rays above 300 GeV, detected by the atmospheric Cerenkov technique, and two apparent detections above 200 TeV with Extensive Air Shower arrays. New experiments now in operation or under construction should significantly improve the Cerenkov flux sensitivity. If very high energy cosmic rays are accelerated in compact regions, they can produce photons and neutrinos by hadronic interactions at levels which are detectable in current or proposed experiments. Observations of both gamma rays and neutrinos provide complementary information about the matter around the source and the proton source spectrum. The optimum conditions at the source for gamma ray and neutrino production by cosmic rays are determined and possible sources and source types are proposed. The status of the now funded DUMAND project, which hopes to detect very high energy astronomical neutrinos, is briefly reviewed. |