  We discus recent developments in theory of high energy two-body break-up
reactions of few-nucleon systems. The characteristics of these reactions are
such that the hard two-body quasielastic subprocess can be clearly separated
from the accompanying soft subprocesses. We discuss in details the hard
rescattering model (HRM) in which hard photodisintegration develops in two
stages. At first, photon knocks-out an energetic quark which rescatters
subsequently with a quark of the other nucleon. The latter provides a mechanism
of sharing the initial high momentum of the photon by the outgoing two
nucleons. Within HRM we discuss hard break-up reactions involving $^2D$ and
$^3He$ targets. Another development of HRM is the prediction of new helicity
selection mechanism for hard two-body reactions, which was apparently confirmed
in the recent JLab experiment.
