  In this paper, we study isoparametric hypersurfaces in Finsler space forms by
investigating focal points, tubes and parallel hypersurfaces of submanifolds.
We prove that the focal submanifolds of isoparametric hypersurfaces are
anisotropic-minimal and obtain the Cartan-type formula in a Finsler space form
with vanishing reversible torsion, from which we give some classifications on
the number of distinct principal curvatures or their multiplicities.
