"...I can recommend anyone to read (his book on) Atjeh and Mekka. His analysis gives a lot of insight and shows the room there is within Islam" – Anwar Ibrahim, in: NRC Handelsblad"...stands as a monument to the work of a great Islamist, and as testimony to much of the inner meaning of one of the world's greatest centres of religion." – William R. Roff, in: Journ. of Asian and African Studies, 1972"...this interesting book of one of the greatest scholars in the field of Islam studies." – in: Bibliotheca Orientalis, 1971"Jan Just Witkam provides a useful introduction about Hurgronje, his background, residence in Arabia, and later work for the Dutch government in the Dutch East Indies." – in: Choice, Nov. 2007"It should become an instant "must-read" to a new generation of scholars and be adopted ... to teach social history, social linguistics, Islam, and the late nineteenth-century history of the Middle East." – Isa Blumi, in: American Journal of Islamic Social Sciences 3 (2008)