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.