  We present a review of the antineutrino spectra emitted from reactors.
Knowledge of these and their associated uncertainties are crucial for neutrino
oscillation studies. The spectra used to-date have been determined by either
conversion of measured electron spectra to antineutrino spectra or by summing
over all of the thousands of transitions that makeup the spectra using modern
databases as input. The uncertainties in the subdominant corrections to
beta-decay plague both methods, and we provide estimates of these
uncertainties. Improving on current knowledge of the antineutrino spectra from
reactors will require new experiments. Such experiments would also address the
so-called reactor neutrino anomaly and the possible origin of the shoulder
observed in the antineutrino spectra measured in recent high-statistics reactor
neutrino experiments.
