The development of semi-empirical electronic structure methods from th
e early 1930s to the present day is reviewed. The emphasis is on the v
alence bond and molecular orbital treatments of molecules but some cov
erage of solids is given, in so far as it follows chemical models. The
current position of such theories in respect of the conceptual insigh
t they provide and their success for predictions of chemical propertie
s is examined. (C) 1998 Elsevier Science B.V.