Today we have heard a series of papers on the developments that have transpired in the past 25 years in the several major disciplines of botany. The recounting of events, highlights, and the work of individuals that have brought their respective fields to their present state of knowledge is in fact the basic materials for the history of botany as a distinct discipline. In a broader context, the endeavor of science, by its nature, is progressive and directive; building on what came before, discarding what is unsound in the light of new information, and finding new approaches or new theories of explanation. History, on the other hand, is reportive and analytical; the good and the bad, the successful and the unsuccessful, as well as the progressive and the retrogressive all deserve consideration. The historian of science faces a dilemma. Should he make value judgments about the course of history saying this line was "good" or that one "bad" or "retrogressive"? Too often it has been shown that the bias of a particular time changes, and what was thought "good" at one time is thought later or by someone else to not be as "good." Further complications of interpretation arise in the breadth of approach made to the study of the history of science or to a particular science. For example, the history of botany, or mycology, or radiation botany could be considered by its students as only consisting of the events and concepts within that science-what is termed internal history. On the other hand, the student might consider the events in the science and its concepts in the broader stage of human activities as they relate directly or indirectly to the history of his science-what is termed external history. How should the historian of botany interpret the changes that have taken place in his science? As a series of sudden overthrows of established theory, procedure, and persons by the new challengers; as a series of revolutions as proposed by Thomas Kuhn (1970)? Or should he interpret the historical