  In most supersymmetric theories, charginos $\tilde{\chi}^\pm_{1,2}$, mixtures
of charged color-neutral gauginos and higgsinos, belong to the class of the
lightest supersymmetric particles. They are easy to observe at $e^+e^-$
colliders. By measuring the total cross sections and the left-right asymmetries
with polarized electron beams in $e^+e^-\to\tilde{\chi}_i^-\tilde{\chi}_j^+
[i,j=1,2]$, the chargino masses and the gaugino-higgsino mixing angles can be
determined. From these observables the fundamental SUSY parameters can be
derived: the SU(2) gaugino mass $M_2$, the modulus $|\mu|$ and $\cos \Phi_\mu$
of the higgsino mass parameter, and $\tan\beta = v_2/v_1$, the ratio of the
vacuum expectation values of the two neutral Higgs doublet fields. The
solutions are unique; the CP-violating phase $\Phi_\mu$ can be determined
uniquely by analyzing effects due to the normal polarization of the charginos.
