  We show that every homeomorphic $W^{1,1}_{\rm loc}$ solution $f$ to a
Beltrami equation $\bar{\partial}f=\mu \partial f$ in a domain $D\subset\Bbb C$
is the so--called lower $Q-$homeomorphism with $Q(z)=K^T_{\mu}(z, z_0)$ where
$K^T_{\mu}(z, z_0)$ is the tangent dilatation of $f$ with respect to an
arbitrary point $z_0\in {\bar{D}}$ and develop the theory of the boundary
behavior of such solutions. Then, on this basis, we show that, for wide classes
of degenerate Beltrami equations $\bar{\partial}f=\mu \partial f$, there exist
regular solutions of the Dirichlet problem in arbitrary Jordan domains in $\Bbb
C$ and pseudoregular and multi-valued solutions in arbitrary finitely connected
domains in $\Bbb C$ bounded by mutually disjoint Jordan curves.
