  Data on the nucleon spin structure suggests that the $u$ (and $d$) quark
distributions in the $\Lambda$ hyperon may be polarized. If this correlation
carries over into fragmentation, then the study of polarized $\Lambda$'s in the
current fragmentation region of deep inelastic lepton scattering will be a
sensitive probe of nucleon spin structure. $\Lambda$ production by polarized
electrons from unpolarized targets can search for this correlation. If it is
signficant, $\Lambda$ production by unpolarized electrons from longitudinally
and transversely polarized targets can probe the $u$-quark helicity and
transversity distributions in the nucleon. We review what is known about quark
polarization in the $\Lambda$, summarize electroproduction of polarized
$\Lambda$s, and estimate the sensitivity to quark polarizations in the nucleon.
We also describe polarization phenomena associated with vector meson
electroproduction that can be observed in the same experimental regime.
