Bengt Sundkler, the great mission scholar, widely known as an international churchman, perhaps had greater recognition in Britain and North America than in his own homeland. A historian of non-European churches, specialising in African church history, he was himself a missionary and a bishop. 

As a missionary in Zululand during the late 1930s his association with the Independent African Churches taught him that the church had to be home for its members. His book Bantu Prophets established his reputation among Africanists as a pioneering scholar of the church in Africa. He became Professor of Church History with Mission History at Uppsala in 1949 and headed the Swedish Institute of Mission Research there from 1951 until his retirement. His studies extended to the Church of South India, and his work as a church historian culminated in A History of the Church in Africa (Cambridge University Press, 2000), written with the assistance of Christopher Steed.

From South Africa, Bengt Sundkler moved with his wide, Ingeborg, to serve the Lutheran church in north-western Tanganyika, bereft of pastors after the internment of the German missionaries with the outbreak of the Second World War. Twenty years later, in the newly independent Tanganyika, the same African church elected him to return and become their first bishop. His Ung Kyrka i Tanganjika (Young Church in Tanganyika) can be seen as the first modern book on mission work in Africa, while of the life of his beloved diocese he wrote Bara Bukoba: Church and Community in Tanzania, published in English, Swahili and Swedish.

This biography was begun by Bengt Sundkler himself. The title, Beyond the Forestline, reflects the gradually extending horizon of a young Swede from the forests of northern Sweden to encompass the ever widening world of international scholarship and ecumenicity. The major part of the book is written by a lifelong friend, Marja-Liisa Swantz, making extensive use of his diaries, letters and notebooks.

Professor Marja-Liisa Swantz, a Finn, has half a century's experience of missionary life, scholarship and development co-operation with Africa, and in particular with Tanzania. Bengt Sundkler was her tutor for doctoral studies at the Univeristy of Uppsala on the ritual and symbolism of the Zaramo of Tanzania. As a senior research fellow in the University of Dar es Salaam she introduced the participative approach to development studies and became the pioneering Africanist and development studies scholar in the University of Helsinski.