  (from the talk:) I shall here speak on gravity in (1+1)-dimensional
space-time --- lineal gravity. The purpose of studying lower dimensional
theories, and specifically lower dimensional gravity, is to gain insight into
difficult conceptional issues, which are present and even more opaque in the
physical (3+1)-dimensional world. Perhaps lessons learned in the
lower-dimensional setting can be used to explicate physical problems. Moreover,
if we are lucky, the lower-dimensional theories can have a direct physical
relevance to modelling phenomena that is actually dynamically confined to the
lower dimensionality. This is what happened with (2+1)-dimensional gravity:
gravitational physics in the presence of cosmic strings (infinitely long,
perpendicular to a plane) is adequately described planar gravity. Indeed the
recently discussed causality puzzles raised by ``Gott time machines'' were
resolved with the help of the lower-dimensional model...
