  The vast majority of the high-energy gamma-ray sources discovered by EGRET
are still unidentified. Percentages range from 50% at high galactic latitudes,
where blazars are responsible for almost all identified sources, to more than
90% near the galactic plane, where isolated neutron stars appear to be the only
certified class of sources of high energy gamma-rays. In spite of all the
efforts devoted to the identification problem, the only success story, so far,
appears to be the chase for Geminga, where X-rays led the way to eventual
optical identification. Similar searches are now starting to produce
encouraging results, although none has reached, as yet, a certified
identification.
