  With the INTEGRAL observatory, ESA has provided a unique tool to the
astronomical community revealing hundreds of sources, new classes of objects,
extraordinary views of antimatter annihilation in our Galaxy, and fingerprints
of recent nucleosynthesis processes. While INTEGRAL provides the global
overview over the soft gamma-ray sky, there is a growing need to perform
deeper, more focused investigations of gamma-ray sources. In soft X-rays a
comparable step was taken going from the Einstein and the EXOSAT satellites to
the Chandra and XMM/Newton observatories. Technological advances in the past
years in the domain of gamma-ray focusing using Laue diffraction have paved the
way towards a new gamma-ray mission, providing major improvements regarding
sensitivity and angular resolution. Such a future Gamma-Ray Imager will allow
studies of particle acceleration processes and explosion physics in
unprecedented detail, providing essential clues on the innermost nature of the
most violent and most energetic processes in the Universe.
