  We investigate properties of two-dimensional asymptotically flat black holes
which arise in both string theory and in scale invariant theories of gravity.
By introducing matter sources in the field equations we show how such objects
can arise as the endpoint of gravitational collapse. We examine the motion of
test particles outside the horizons, and show that they fall through in a
finite amount of proper time and an infinite amount of coordinate time. We also
investigate the thermodynamic and quantum properties, which give rise to a
fundamental length scale. The 't Hooft prescription for cutting off eigenmodes
of particle wave functions is shown to be source dependent, unlike the
four-dimensional case. The relationship between these black holes and those
considered previously in $(1+1)$ dimensions is discussed.

High Energy Physics - Theory