Simultaneous multiwavelength observations of gamma-emitting blazars

During Phase 3 of the Compton Gamma Ray Observatory Mission, the EGRET Instrument Team has worked with a large collaboration of observers at other frequencies to obtain multiwavelength coverage simultaneous with EGRET observations of a substantial number of blazars, with emphasis on those which had been detected previously by EGRET at energies >100 MeV. The goal of this program was twofold: to search for correlated time variations in different frequency bands, and to obtain simultaneous spectra from the GHz radio range to GeV gamma-ray energies. A sample of early results on both time variations and spectra will be presented.