These Lecture Notes focus on the physics of relativistic jet sources in the universe, from galactic microquasars to active galactic nuclei (AGN). The early 21st century is an epoch in which a large number of high-energy astronomical missions are underway (RossiXTE, Chandra, XMM-Newton, INTEGRAL, Swift, Suzaku). The wealth of X-ray and gamma-ray data, coupled with ground-based observations in the optical/IR/radio bands, provides an increasing amount of information on microquasars, allowing the investigation of the physical processes for the formation and the evolution of relativistic jets, as well as their relation to the accretion process. The information obtained from galactic relativistic |