The structural complexity of lignin has continually challenged the in genuity of researchers to develop suitable methods for its charac terization prior to and following a wide variety of chemical, biologi cal, and physical treatments. Initially, activity along these lines was fueled by a desire to interpret technical delignification (Le., pulping) processes in terms of accompanying structural changes in the lignin. Subsequently, increasingly wide ranging, in-depth investigations on the structure and reactivity of lignin exposed the inadequacy of many of the methods currently in use and...