  Blazars exhibit flux and spectral variations of largest amplitude at the
highest frequencies. Therefore, monitoring their variability at X- and
gamma-rays is the most effective tool to peer into the mighty powerhouse of
these sources. High energy observations of the brightest blazars with the
latest generation of satellites have allowed a detailed study of their behavior
and have critically improved our understanding of the physics of blazar jets. I
will review some of the recent results of blazar multiwavelength monitoring
with emphasis on the X-ray campaigns accomplished with BeppoSAX and I will
describe some of the future programs for blazar investigation from space,
particularly with INTEGRAL.
