Students of a phenomenon as common but complex as andesite genesis often
are overwhelmed by, or overlook, the volume and diversity of relevant
information. Thus there is need for periodic overview even in the
absence of a dramatic breakthrough which "solves the andesite problem"
and even though new ideas and data keep the issues in a state of flux.
Thus I have summarized the subject through mid-1980 from my perspective
to help clarify the long-standing problem and to identify profitable
areas for future research. Overviews are more easily justified than
achieved and there are fundamental differences of opinion concerning how
to go about them. It is professionally dangerous and therefore uncom-
mon for single authors, especially those under 35 such as I, to
summarize a broad, active field of science in book-length thor-
oughness. Review articles in journals, multi-authored books, or symposia
proceedings appear instead. The single-authored approach is intimidating
in scale and can result in loss of thoroughness or authority on
individual topics. The alternatives lack scope or integration or both.