  I will review recent advances in the field of blazars, highlighting the
contribution of Swift. Together with other operating satellites (most notably
Fermi, but also AGILE, WISE, Planck) and ground based facilities such as
Cherenkov telescopes, Swift was (and is) crucial for improving our
understanding of blazars. The main advances in the blazar field made possible
by Swift includes the opening of the time domain investigation, since there are
several sources with hundreds of simultaneous optical, UV and X-ray data taken
at different times; the possibility to measure the black hole mass in very
powerful blazars, that show clear signs of accretion disk emission; the
possibility to classify blazar candidates, through X-ray observations; the
finding of the most powerful and distant blazars, emitting strongly in the hard
X-ray band accessible to Swift/BAT. All these improvements had and have a great
impact on our understanding on how relativistic jets are formed and emit, on
their power, and on how the heavy black holes in these systems first formed and
grew.
