BRIDGETOWN, Barbados - SCHOLARSHIP on the contemporary political history of the Caribbean can benefit from the autobiographies, memoirs, papers and correspondence of political leaders, especially prime ministers. This is a well-developed and invaluable tradition in England and the United States, motivated in the former by an overweening sense of the importance of their history and the latter by the possibility of lucrative gains. Every former president has at least one book giving his version of history. Mr. Owen Arthur, the former three-term prime minister of Barbados has relinquished the role of Leader of the Opposition after his party narrowly lost the recent general election. Several aspects of this development are significant, starting with the