  We present measurements of the flavor-changing neutral current decays B -->
Kl+l- and B --> K*l+l-, where l+l- is either an e+e- or mu+mu- pair. The data
sample comprises 229 x 10^6 Y(4s) -->to BBbar decays collected with the BaBar
detector at the PEP-II e+e- storage ring. Flavor-changing neutral current
decays are highly suppressed in the Standard Model and their predicted
properties could be significantly modified by new physics at the electroweak
scale. We measure the branching fractions B(B --> Kll) = (0.34 +- 0.07 +- 0.02)
x 10^{-6}, B(B --> K*ll) = (0.78^{+0.19}_{-0.17} +- 0.11) x 10^{-6}, the direct
CP asymmetries of these decays, and the relative abundances of decays to
electrons and muons. For two regions in l+l- mass, above and below m(Jpsi), we
measure partial branching fractions and the forward-backward angular asymmetry
of the lepton pair. In these same regions we also measure the K* longitudinal
polarization in B --> K*l+l- decays. Upper limits are obtained for the lepton
flavor-violating decays B --> Kemu and B --> K*emu. All measurements are
consistent with Standard Model expectations.
