  In these notes we review the theory of the microscopic modeling of the 5-dim.
black hole of type IIB string theory in terms of the $D1-D5$ brane system. The
emphasis here is more on the brane dynamics rather than on supergravity
solutions. We present a discussion of the low energy brane dynamics and account
for black hole thermodynamics and Hawking radiation rates. These considerations
are valid in the regime of supergravity due to the non-renormalization of the
low energy dynamics in this model.
