This impressive book is a well-researched case study of socio-economic change caused by the production, distribution and consumption of khat in eastern Ethiopia since the late nineteenth century.

- James Quirin, JOURNAL OF AFRICAN HISTORY

In Leaf of Allah, the first social and economic history of Khat in Ethiopia and surrounding lands of which I am aware, Gebissa explores the dramatic growth in its production, and its impact on the region where it is grown. In the process, he has immersed himself not just in the literature but also in the lives of Harerge farmers and traders, producing a book that is constantly fascinating.

- Christopher Clapham, TLS

Ezekiel Gebissa writes with a fluency that comes from a vivid interest in the subject, and the khat producers and traders of the Harer highlands come to life in his hands, often in their own words. He has done them proud.

- Christopher Clapham, GHANA TIMES