  We use observations from the CASTLES survey of gravitational lenses to study
extinction in 23 lens galaxies with $0 < z_l < 1$. The median differential
extinction between lensed images is $\Delta E(\bv) = 0.05$ mag, and the
directly measured extinctions agree with the amount needed to explain the
differences between the statistics of radio and (optical) quasar lens surveys.
We also measure the first extinction laws outside the local universe, including
an $R_V=7.2$ curve for a molecular cloud at $z_l=0.68$ and an $R_V=1.5$ curve
for the dust in a redshift $z_l=0.96$ elliptical galaxy.
