In June 1967 the Canadian National Commission for Unesco and the Universit' de Moncton jointly sponsored an international seminar on bilingualism. Although 1967 was Canada's centennial year, the seminar was concerned only incidentally with bilingualism in Canada. Instead, bilingualism was considered as the essential element in communication between language irrespective of national boundaries. Participants included linguists, psychologists, and sociologists. The report shows that the interdisciplinary discussions carried on at Moncton were fruitful; that significant questions about bilingualism were raised and an improvement in communication between specialists from different traditions, languages, and cultures were effected. This volumes makes a valuable contribution toward establishing a general theory of bilingualism.