  A next generation Gamma Ray Burst (GRB) mission to follow the upcoming Swift
mission is described. The proposed Energetic X-ray Imaging Survey Telescope,
EXIST, would yield the limiting (practical) GRB trigger sensitivity, broad-band
spectral and temporal response, and spatial resolution over a wide field. It
would provide high resolution spectra and locations for GRBs detected at GeV
energies with GLAST. Together with the next generation missions
Constellation-X, NGST and LISA and optical-survey (LSST) telescopes, EXIST
would enable GRBs to be used as probes of the early universe and the first
generation of stars. EXIST alone would give ~10-50" positions (long or short
GRBs), approximate redshifts from lags, and constrain physics of jets, orphan
afterglows, neutrinos and SGRs.
