This book is the first complete translation into English of Imam Muhammad ibn al-Hasan al-Shaybani’s (729-804) Kitab al-Kasb or The Book of Earning a Livelihood. An important, authoritative early ethico-juristic treatise in classical Islamic economic thought. The translator has also introduced and lightly annotated the text, and pointed out the deep relevance of this work for our current rethinking and redefining of the science of economics in terms of its ends (viz., provisioning for livelihood = infaq) rather than its means (viz., allocation of resources), and thereby reviving a true economy of sustainable, livelihoods for the common good (al-maslahah al-‘ammah).