Abstract
Recent developments of the synchrotron radiation facilities and intense lasers are now guiding us to new research frontiers with a high energy GeV photon beam and an intense and short pulse MeV γ-ray beam. New directions of the science developments with photo-nuclear reactions are discussed. The inverse Compton yrays have good characteristics as 1) good emmitance, 2) high linear and circular polarization. With these advantages, the photon beams in the energy range from MeV to GeV are used for studying hadron structure, nuclear structure, astrophysics, materials science, as well as for applying medical science.
