  Application of a sufficiently strong parallel magnetic field $B_\parallel >
B_{c}$ produces a soliton-lattice (SL) ground state in a double-layer quantum
Hall system. We calculate the ground-state properties of the SL state as a
function of $B_\parallel$ for total filling factor $\nu_{T}=1$, and obtain the
total energy, anisotropic SL stiffness, Kosterlitz-Thouless melting
temperature, and SL magnetization. The SL magnetization might be experimentally
measurable, and the magnetic susceptibility diverges as $|B_\parallel -
B_{c}|^{-1}$.
