  We review the historical developments leading to the
Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix. Present status of the CKM
matrix from direct measurements is summarized, giving also the present profile
of the unitarity triangle. CP Violation in the $K^0$ - $\bar{K^0}$ complex and
in $B$-meson decays are discussed in the context of the CKM matrix.
