The past decade has witnessed major advances in our understanding of the
chemical composition, structure, and reactivity of the complex
organic-rich fossil matter known as "coal. " Nevertheless, important
scientific questions concerning molecular weight distributions, degree
of crosslinking, typical duster sizes, type of interconnecting bridges,
the possible role of a "mobile phase," and the nature of organic sulfur
forms remain topics of heated debate. Moreover, there appears to be a
notable lack of consensus regarding the overall direction and goals of
structural elucidation work. Is it worthwhile to study whole coal
samples, or should we separate out the various, more or less
well-defined, maceral and mineral constituents before attempting to
describe the structural and compositional features of coal at the
molecular Ievel? Second, should there be more emphasis on key structural
features and average statistical parameters, or is it necessary to
identify individual chemical structures in considerable detail? From the
developments of the past decade it is clear that advanced spectroscopic
techniques are playing an increasingly important role in resolving
difficult questions with regard to the chemical structure and
composition of coal. Moreover, it has become equally clear that no
single spectroscopic approach can provide all the answers but multiple
techniques need to be used in a highly integrated and synergistic
manner.