  We compute by numerical transfer-matrix methods the surface free energy
$\tau(T),$ the surface stiffness coefficient $\kappa(T),$ and the single-step
free energy $s(T)$ for Ising ferromagnets with $(\infty \times L)$
square-lattice and $(\infty \times L \times M)$ cubic-lattice geometries, into
which an interface is introduced by imposing antiperiodic or plus/minus
boundary conditions in one transverse direction. These quantities occur in
expansions of the angle-dependent surface tension, either for rough or for
smooth interfaces. The finite-size scaling behavior of the interfacial
correlation length provides the means of investigating $\kappa(T)$ and $s(T).$
The resulting transfer-matrix estimates are fully consistent with previous
series and Monte Carlo studies, although current computational technology does
not permit transfer-matrix studies of sufficiently large systems to show
quantitative improvement over the previous estimates.
