  e-ASTROGAM (`enhanced ASTROGAM') is a breakthrough Observatory mission
dedicated to the study of the non-thermal Universe in the photon energy range
from 0.3 MeV to 3 GeV. The mission is based on an advanced space-proven
detector technology, with unprecedented sensitivity, angular and energy
resolution, combined with polarimetric capability. In the largely unexplored
MeV-GeV domain, e-ASTROGAM will open a new window on the non-thermal Universe,
making pioneering observations of the most powerful Galactic and extragalactic
sources, elucidating the nature of their relativistic outflows and their
effects on Galactic ecosystems. With a line sensitivity in the MeV energy range
one to two orders of magnitude better than previous generation instruments,
will determine the origin of key isotopes fundamental for the understanding of
supernova explosion and the chemical evolution of our Galaxy. The mission will
provide unique data of significant interest to a broad astronomical community,
complementary to powerful observatories such as LIGO-Virgo-GEO600-KAGRA, SKA,
ALMA, E-ELT, TMT, LSST, JWST, Athena, CTA, IceCube, KM3NeT, and the promise of
eLISA.
  Keywords: High-energy gamma-ray astronomy, High-energy astrophysics, Nuclear
Astrophysics, Compton and Pair creation telescope, Gamma-ray bursts, Active
Galactic Nuclei, Jets, Outflows, Multiwavelength observations of the Universe,
Counterparts of gravitational waves, Fermi, Dark Matter, Nucleosynthesis, Early
Universe, Supernovae, Cosmic Rays, Cosmic antimatter.
