Semileptonic and Leptonic Charm Decays at CLEO-c

Using e+e- collision data in the sqrt{s} = 4 GeV energy region, CLEO-c has made extensive studies of semileptonic and leptonic decays of the D0, D+, and Ds+ charmed mesons. We report recent measurements of absolute branching fractions, form factors, and decay constants that serve as precision tests of theoretical calculations.