The historic long term economic interconnections of the world are now universally accepted. The idea of the economic 'world system' advanced by Immanuel Wallerstein has set the period of linkage in the early modern period but Andre Gunder Frank and Barry K. Gills think that this date is much too late. They argue an interconnection going back as much as 5000 years. In The World System, leading academics examine this issue, in a debate contributed to by William H. McNeill and Immanuel Wallerstein among others.