wallerstein's work developed at a time when the dominant approach to understanding development, modernization theory, was under attack from many front, and he followed suit.He himself acknowledges that his aim was to create an alternative explanation . He aimed at achieving "a clear conceptual break with theories of modernization and thus provide a new theoretical paradigm to guide our investigations of the emergence and development of capitalism, industrialism and national states. Criticisms to modernization include (1) the reification of the nation-state as the sole unit of analysis, (2) assumption that all countries can follow only a single path of evolutionary development, (3) disregard of the world-historical development of transnational structures that constrain local and national development (4) explaining in terms of a historical ideal types of "tradition" versus "modernity", which are elaborated and applied to national cases. In reacting to modernization theory, wallerstein outlined a research agenda with five major subjects:the functioning of the capitalist world economy as a system , the how and why of its origins,its reltions with non capitalist structures in previous centuries, comparative study of alternative modes of production and the ongoing transition to socialism