  We review the progress that has been made in observing and analyzing
molecular cloud structure in recent years. Structures are self-similar over a
wide range of scales with similar power law indices independent of the star
forming nature of a cloud. Comparison of structures at parsec-scale resolution
in a star forming and non-star forming cloud show that the average densities in
the former are higher but the structural characteristics in each cloud are much
the same. In gravitationally bound regions of a cloud, however, and at higher
densities and resolution, the self-similar scaling relationships break down and
it is possible to observe the first steps toward star formation. High
resolution observations of the dense individual star forming cores within the
clumps hold the key to an empirical understanding of the origins of the stellar
initial mass function.
