The Managerial Control and Accounting Information Processing schools are the earliest examples of BAR. The former draws directly on the seminal work of Argyris [1952]. The latter is an outgrowth of problems present in financial accounting during the 1950s and 1960s. Over the past 30 years, both the questions researched by these two schools and the methods used to research them have changed. The other three schools are more recent in their origins. The first two date from the mid-1970s and the Organizational Sociology school in BAR began in the 1980s. Special note is taken in the discussion of the Organizational Sociology's unique orientation among BAR schools both intellectually and methodologically. It is conjectured that in the future this could be a significant factor in organizing and understanding BAR.