Given a representation of a classical knot group onto a quotient group
E/A, we address the classification of lifts of that representation on
to E. The classification is given first in terms of classical obstruct
ion theory and then, in many cases, interpreted in terms of the homolo
gy of covers of the knot complement. Applications include the study of
dihedral, metacyclic, and metabelian representations. Properties of t
he restrictions of lifts to the peripheral subgroup are also studied.