Enhanced fluxes of low-energy electrons backstreaming from the earth's bow shock have been identified at ISEE 3. When present, these fluxes modify ambient solar wind electron velocity distributions f(v) in characteristic ways that depends on whether ISEE 3 is near the edge, or within the interior of the earth's electron foreshock. Near the edge, energy peaks in f(v) are observed. Such distributions should be locally unstable to electron plasma oscillations. Well within the interior of the foreshock, enhanced fluxes of electrons with energies up to the maximum detected by the Los Alamos electron analyzer (~1 keV) are observed over the full backward hemisphere. These electrons can be modelled with an asymptotic power law distribution having index in the range 4≲pbs≲6. At intermediate energies (~20--50 eV), twin angular peaks are observed centered on the magnetic field direction ?. Also observed at these times are depressions in f(v) at energies less than ~20 eV that are centered on ?. Such distributions having a perpendicular temperature greater than their parallel temperature may be locally unstable to the generation of whistler waves. Analysis of a particularly clean example of connection to the bow shock is consistent with the possiblility that the observed electron fluxes emerge from the forward foot of the electron heating region within bow shock where the electron density and temperature are larger than that of the uperturbed upstream solar wind by a factor of ~1.2. This analysis also indicates that the electrostatic potential within the forward foot of the shock is between ~5 and 50 V more positive than that within plasma far upstream at ISEE 3. However, these interpretations depend on the assumption of nearly scatter-free propagation, which may not hold. Using parameters derived from model fits to measured velocity distributions, we estimate ~10-4 of the incident solar wind electrons are accelerated by the bow shock back into the upstream region with energies greater than 1 keV.