This dissertation is incorporated a cross-disciplinary range of perspectives in research. There is theological, historical and empirical research. Its essence consists therefore of a case study in the history of the international missionaries of the Assemblies of God in Great Britain and Northern Ireland 1965-2000. It does not attempt to simply relate a chronological account of what people did in various areas of the world. Rather it attempts to map the understanding of `the divine call' to mission work as perceived by these missionaries. This is fitted into the context of the time, politically, socially and economically as well as missiologically. The history of the understanding of `the divine call' through the centuries assists the understanding of how 20`h Century people understand call. Then this is narrowed down to the Pentecostal fellowship known as the Assemblies of God. The research is conducted from the perspective of the home nation, the denominational directors of world mission and the missionaries themselves. The main sources are the original Minutes of the agency, their magazines and firsthand accounts through the means of questionnaires of the available missionaries; this is shown to be representative of the whole group from 1965-2000. The debate leads from the assumptions of an individualistic understanding of a primary and secondary `call', first to discipleship, secondly to a specific task in a specific location or operating from a specific gift, and on to a third aspect of how the local home churches themselves should be participants in the callings of their missionaries. This provides a more integrated missiology which is both pneumatological (in terms of receiving God's revelation by his Spirit) and ecclesiological.