Some results are reported of an investigation into the meanings of the English modal auxiliary verbs. The corpus consisted of the one million word Brown University corpus of American English and a matching Lancaster University corpus of British English. The three factors operative in the study were: (1) contextual features, that is, co-occurring syntactic/semantic features of the text; (2) British and American English; and (3) differences of genre or style. A theoretical investigation revealed that an appropriate model would have to synthesize six orientations: mono-semantic, polysemantic, categorical, non-categorical, logical, and pragmatic. In addition, a new definition was given to the epistemic/root distinction. Here, epistemic refers to a speaker's belief regarding the truth of a proposition; root refers to a phenomenon which is influenced by some other phenomena. In the four pairs of modals discussed here, should/ought, must/have to, shall/will, and can/may, a compensatory relationship between British and American usage was found in each case. In other words, the American use of the first member of each pair was balanced by the British use of tbe second member. It is noted, in conclusion, that this analysis of written texts is to be supplemented by an analysis of spoken material. (AMH)