  We report the first detection of a credible progenitor system for a Type Ic
supernova (SN Ic), SN 2017ein. We present spectra and photometry of the SN,
finding it to be similar to carbon-rich, low-luminosity SNe Ic. Using a
post-explosion Keck adaptive optics image, we precisely determine the position
of SN 2017ein in pre-explosion \hst\ images, finding a single source coincident
with the SN position. This source is marginally extended, and is consistent
with being a stellar cluster. However, under the assumption that the emission
of this source is dominated by a single point source, we perform point-spread
function photometry, and correcting for line-of-sight reddening, we find it to
have $M_{\rm F555W} = -7.5\pm0.2$ mag and $m_{\rm F555W}-m_{\rm
F814W}$=$-0.67\pm0.14$ mag. This source is bluer than the main sequence and
brighter than almost all Wolf-Rayet stars, however it is similar to some WC+O-
and B-star binary systems. Under the assumption that the source is dominated by
a single star, we find that it had an initial mass of $55\substack{+20-15}
M_{\odot}$. We also examined binary star models to look for systems that match
the overall photometry of the pre-explosion source and found that the
best-fitting model is a $80$+$48 M_{\odot}$ close binary system in which the
$80 M_{\odot}$ star is stripped and explodes as a lower mass star. Late-time
photometry after the SN has faded will be necessary to cleanly separate the
progenitor star emission from the additional coincident emission.
