  A workshop on The Next Generation Gamma-Ray Sources sponsored by the Office
of Nuclear Physics at the Department of Energy, was held November 17--19, 2016
in Bethesda, Maryland. The goals of the workshop were to identify basic and
applied research opportunities at the frontiers of nuclear physics that would
be made possible by the beam capabilities of an advanced laser Compton beam
facility. To anchor the scientific vision to realistically achievable beam
specifications using proven technologies, the workshop brought together experts
in the fields of electron accelerators, lasers, and optics to examine the
technical options for achieving the beam specifications required by the most
compelling parts of the proposed research programs. An international assembly
of participants included current and prospective $\gamma$-ray beam users,
accelerator and light-source physicists, and federal agency program managers.
Sessions were organized to foster interactions between the beam users and
facility developers, allowing for information sharing and mutual feedback
between the two groups. The workshop findings and recommendations are
summarized in this whitepaper.
