Title: 75 Pegasi, a very-short-period extreme mass ratio binary
Abstract: The bright star 75 Peg has long been known to be a spectroscopic binary. The orbital parameters are presented here for the first time, and include the very short period of 0d.5021035. The system has one of the most extreme values of mass ratio known. The most direct interpretation of the available spectroscopic observations leads to the conclusion that the primary fills, or is very close to filling, its critical Roche lobe, and will begin to lose mass to its companion before leaving the main sequence.