A major limitation and a continuing source of confusion in the interpretation of molecular line observations has been the large degree of chemical complexity that is observed in star-forming molecular cores. The past decade has seen dramatic improvements in our ability to extract chemical information from molecular line observations. These advances have been driven by new observational platforms and techniques that use combined studies of molecular emission and dust emission/absorption to derive chemical abundances. I will outline the various methods and uncertainties in computing chemical information from observations and discuss these new techniques that allow for the estimation of line of sight structure in molecular abundance in both quiescent and active star forming regions. I will show how improved chemical knowledge can be used to place stronger constraints on theoretical astrochemical models, but also open new avenues in the use of molecular emission to examine the physics of molecular clouds and star formation. Thus, we can begin the process of unraveling the chemical complexities and more fully realize the long-standing promise of molecular line observations.

8 pages, 6 figures in text, From Fourth Cologne-Bonn-Zermatt-Symposium, The Dense Interstellar Matter in Galaxies