It is shown that classical nonsupersymmetric Yang-Mills theory in four
dimensions is symmetric under a generalized dual transform which redu
ces to the usual dual operation for electromagnetism. The parallel p
hase transport (A) over tilde(mu)(x) constructed earlier for monopoles
is seen to function also as a potential in giving a full description
of the gauge field, playing thus an entirely dual symmetric role to th
e usual potential A(mu)(x). Sources of A are monopoles of (A) over til
de and vice versa, and the Wu-Yang criterion for monopoles is found to
yield as equations of motion the standard Wong and Yang-Mills equatio
ns for the classical and Dirac point charge, respectively; this applie
s whether the charge is electric or magnetic, the two cases being rela
ted just by a dual transform. The dual transformation itself is explic
it, though somewhat complicated, being given in terms of loop space va
riables of the Polyakov type.