ASTROGAM will be optimized for the 0.3 MeV Ė 100 MeV energy range, extending up to GeV energies. It combines for the first time excellent angular resolution with optimal detection capability in both the Compton scattering and the pair production regimes. Furthermore, it opens up an entirely new observational window on the high-energy universe as the first gamma-ray telescope with fully characterized polarimetric capability. ASTROGAM will investigate the Universe in the mostly unexplored energy domain 0.3-100 MeV. The mission science drivers can be grouped into three main themes:

ASTROGAM data will be crucial to answer as yet unsolved basic questions in high-energy astrophysics and fundamental physics, with important contributions to solar and terrestrial physics. ASTROGAM will resolve a large number of outstanding theoretical issues regarding the most energetic processes of our Universe. We summarize here the main lines of investigation that will be addressed by the mission.

Besides these three main themes, ASTROGAM will be ideal for the study of high-energy sources in general, both Galactic and extragalactic, including pulsars and pulsar wind nebulae, accreting neutron stars and black holes, SNRs, soft gamma-ray repeaters, magnetars, GRBs, AGNs. A dedicated program for a very fast detection of transients will be implemented with emphasis on Target of Opportunity observations.