  This thesis describes the measurement and analysis of the transmission matrix
(TM) for microwave radiation propagating through multichannel random waveguides
in the crossover to Anderson localization. Eigenvalues of the transmission
matrix and the associated eigenchannels are obtained via a singular value
decomposition of the TM. The sum of the transmission eigenvalues yields the
transmittance $\it T$, which is the classical analog of the dimensionless
conductance $\textsl g$. The dimensionless conductance $\textsl g$ is the
electronic conductance in units of the quantum conductance, $G/(e^2/h)$.
