  Gamma-ray astronomy presents an extraordinary scientific potential for the
study of the most powerful sources and the most violent events in the Universe.
In order to take full advantage of this potential, the next generation of
instrumentation for this domain will have to achieve an improvement in
sensitivity over present technologies of at least an order of magnitude. The
DUAL mission concept takes up this challenge in two complementary ways: a very
long observation of the entire sky, combined with a large collection area for
simultaneous observations of Type Ia SNe. While the Wide-Field Compton
Telescope (WCT) accumulates data from the full gamma-ray sky (0.1-10 MeV) over
the entire mission lifetime, the Laue-Lens Telescope (LLT) focuses on 56Co
emission from SNe Ia (0.8-0.9 MeV), collecting gamma-rays from its large area
crystal lens onto the WCT. Two separated spacecraft flying in formation will
maintain the DUAL payloads at the lens' focal distance.
