  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.
