  The high-energy and high-luminosity data-taking campaigns of the LEP e^+e^-
collider provided the four collaborations, ALEPH, DELPHI, L3 and OPAL, with
about 50000 W-boson pairs and about a thousand singly-produced W bosons. This
unique data sample has an unprecedented reach in probing some aspects of the
Standard Model of the electroweak interactions, and this article reviews
several achievements in the understanding of W-boson physics at LEP. The
measurements of the cross sections for W-boson production are discussed,
together with their implication on the existence of the coupling between Z and
W bosons. The precision measurements of the magnitude of triple gauge-boson
couplings are presented. The observation of the longitudinal helicity component
of the W-boson spin, related to the mechanism of electroweak symmetry breaking,
is described together with the techniques used to probe the CP and CPT
symmetries in the W-boson system. A discussion on the intricacies of the
measurement of the mass of the W boson, whose knowledge is indispensable to
test the internal consistency of the Standard Model and estimate the mass of
the Higgs boson, concludes this review.
