This is an uncommly brilliant work in social theory and sociology. Moreover, economic sociology was founded through "Economy and Society", especially its second chapter ("Sociological Categories of Economic Action") which is the size of a small book (approx. 200 pages).
The general theoretical approach of Weber can be characterized as one of "interpretive economic sociology", that is, as a type of economic sociology in which the concept of "meaning" is at the very center of the explanatory exercise.
Social action (to follow Ch. 1) is defined as a type of behavior to which meaning is attached ("action"), and which is oriented to the behavior of others ("social"). Economic sociology consequently deals with "economic social action".
"Economy and Society" was part of a larger work entitled "Handbook of Social Economics", which included volumess on "Economy and Nature", "Economy and Technology" - and "Economy and Society". In his work Weber explores such topics as "economy and law", "economy and religion", "economy and politics", and much more.
The work "Economy and Society", finally, is a bric-a-brac. Weber himself only sent 4 chs to the printer (=Chs 1-4). The rest of the 2 volumes consists of manuscripts that his wife and economist Melchior Palyi put together, pretty much as they saw fit. Caution is consequently necessary when reading "Economy and Society"; and this work should not be treated as "a book" by Weber.