  Identifying gamma-ray sources in the Galaxy is hampered by their poor
localization, source confusion, and the large variety of potential emitters.
Neutron stars and their environment offer various ways to power gamma-ray
sources: pulsed emission from the open magnetosphere and unpulsed gamma rays
from the wind nebula and from the cosmic rays accelerated in the supernova
remnant. While the latter still awaits confirmation, new candidate associations
bring forward the importance of 10-kyr old pulsars as GeV sources, with a
diversity that will help constrain the acceleration mechanisms near the pulsar
and in the wind. Theoretical interest in the gamma-ray activity of X-ray
binaries and micro-quasars has also been revived by the emergence of a subset
of variable sources in the inner Galaxy and another one in the halo.
