  A summary of studies of electroweak top-quark production performed by the CMS
collaboration is presented. The results include measurements of production
cross sections, extraction of the value of $|V_{tb}|$, determination of W-boson
helicity in top-quark decays and top-quark spin asymmetry, and a search for
anomalous couplings in the Wtb vertex. No deviations from predictions of the
standard model are found.
