  By directly probing mass distributions, gravitational lensing offers several
new tests of the CDM paradigm. Lens statistics place upper limits on the dark
matter content of elliptical galaxies. Galaxies built from CDM mass
distributions are too concentrated to satisfy these limits, so lensing extends
the ``concentration problem'' in CDM to elliptical galaxies. The central
densities of the model galaxies are too low on ~10 pc scales to agree with the
lack of central images in observed lenses. The flux ratios of four-image lenses
imply a substantial population of dark matter clumps with a typical mass ~10^6
Msun. Thus, lensing implies the need for a mechanism that reduces dark matter
densities on kiloparsec scales without erasing structure on smaller scales.
