The term accounting theory has several definitions. For the purposes of major reference collection, accounting theory is here broadly defined as the basic assumptions, definitions, principles and concepts - and how we derive them - that underlie accounting rule making by a legislative body as well as the reporting of financial information. The major work starts with a philosophical overview of accounting, including accounting theory. Among the issues examined are whether accounting is an art or a science and whether or not it can be value free. Also examined is the question of whether any preconditions are necessary to establish a viable approach to accounting theory. The set then goes on to touch on the following themes: informally developed concepts; conceptual frameworks; accounting for changing prices; applied accounting theory; agency theory (also called contract theory); the true and fair view, or principles-based versus rules-based standards; and international accounting and convergence.