  The International Gamma-Ray Astrophysics Laboratory, i.e. the INTEGRAL
satellite of ESA, in orbit since about 3 years, performs gamma-ray observations
of the sky in the 15 keV to 8 MeV energy range. Thanks to its imager IBIS, and
in particular the ISGRI detection plane based on 16384 CdTe pixels, it achieves
an excellent angular resolution (12 arcmin) for point source studies with good
continuum spectrum sensitivity. Thanks to its spectrometer SPI, based on 19
germanium detectors maintained at 85 K by a cryogenic system, located inside an
active BGO veto shield, it achieves excellent spectral resolution of about 2
keV for 1 MeV photons, which permits astrophysical gamma-ray line studies with
good narrow-line sensitivity. In this paper we review some goals of gamma-ray
astronomy from space and present the INTEGRAL satellite, in particular its
instruments ISGRI and SPI. Ground and in-flight calibration results from SPI
are presented, before presenting some selected astrophysical results from
INTEGRAL. In particular results on point source searches are presented,
followed by results on nuclear astrophysics, exemplified by the study of the
1809 keV gamma-ray line from radioactive 26Al nuclei produced by the ongoing
stellar nucleosynthesis in the Galaxy. Finally a review on the study of the
positron-electron annihilation in the Galactic center region, producing 511 keV
gamma-rays, is presented.
