  The EGRET instrument onboard of CGRO detected a number of gamma-ray flares
from blazars, and it is expected that GLAST, to be launched in 2006, should
detect many more such flares. These flares should be preceded by X-ray
precursors, and the MAXI All-Sky Monitor, to be deployed around the time of
launch of GLAST, is likely to detect such precursors. This paper highlights the
interesting new insights into the structure of jets in blazars that may result
from simultaneous X-ray and gamma-ray observations. In particular, it addresses
the expected temporal relationship between the precursors and flares, and the
expected luminosities of the precursors.

Astrophysics