1 1 orbita1 theory has had some notable successes in the ana1ysis of
individua1 organic reactions and in corre1ations between reaction
series. Gen- ll? the theory has invoked to exp1ain known chemica1
phenomena, and rather infrequent1y [ broad1y-based predictions. In 1965
Woodward and published ? series of papers the 1 1 orbita1 inter-
pretation of various types of concerted cyc10-addition reactions, which
hitherto had rather 1? understood. Because these processes (now known as
pericyclic reactions) had great synthetic importance, and because the
Woodward-Hoffmann theory was stated so explicit1y as to allow [ usefu1
and far-reaching predictions to made, the genera1 acceptance of the
so-called Woodward-Hoffmann Ru1es was very rapid. Judging from the vast
number of publications that have appeared, ? great dea1 of
experimentaleffort has channelled into this genera1 area since that
time, the results of which provide ? vindication of the ru1es. The
theoretica1 basis of Woodward and Hoffmann's method has, however, the
subject of criticism and controversy, and ? of alternative theoretica1
methods have a1so appeared. university departments (inc1uding?ur own)
have for some time covered pericyclic reactions in their undergraduate
and graduate courses. Because aims, teaching methods, and persona1
preferences differ wide1y, each of the various theoretica1 methods have
achieved some currency. We have sought to?1 these methods in some sort
of perspective. The book is intended to introductory, being aimed
primarily at fina1 year undergraduates and first year postgraduates.
