Few economic problems have attracted as much of the attention of the world's leading economists and stirred up such lively debates between them as the transfer problem. Classical writers such as David Ricardo, David Hume and others, had heated debates with contemporaries on the consequences of balance-of-payments disequilibria (a temporary transfer). The most famous debate, however, was the discussion between John Maynard Keynes and Bertil Ohlin, which led to the first systematic treatment of the consequences of transfers as such. This debate was also primarily directed at the causes and consequences of possible balance-of payments disequilibria. The early attention on balance-of-payments problems following a transfer is somewhat in contrast with today's interest in the transfer problem, which is mostly concerned with welfare effects. For example, the welfare effects associated with development assistance have been considered by Jan Tinbergen (1976), who regards development aid from the North to the South as a means of obtaining greater equality between nations. Moreover, he is convinced that development aid is necessary to increase welfare levels in the developing world. Needless to say, there is no general agreement between economists on the influence of development aid on welfare. Nor is there agreement on whether or not development assistance is necessary in the first place in order to put a country on a more rapid path to development. There are not only disagreements and discussions on the practical consequences of transfers, but also disagreements between modern theorists on the effects of transfers and how to model them.