  We study quasi-stationary physical process for black holes within the context
of Lanczos-Lovelock gravity. We show that the Wald entropy of stationary black
holes in Lanczos-Lovelock gravity monotonically increases for quasi-stationary
physical processes in which the horizon is perturbed by the accretion of
positive energy matter and the black hole ultimately settles down to a
stationary state. This result reinforces the physical interpretation of Wald
entropy for Lanczos-Lovelock models and takes a step towards proving the
analogue of the black hole area increase-theorem in a wider class of
gravitational theories.
