The mathematical works of Ab? K?mil (floruit circa 880) were produced two generations after the works of Al-Khwarizm?, the founder of algebra. They opened up fields of research that proved fertile up until the seventeenth century, and were soon to become both a reference and a model. Their influence was decisive on the development of algebra in Arabic no less than in Latin and Hebrew. There will be found in the present publication the first rigorously critical edition of Ab? K?mil s works, as well as the first ever translation into a modern language. Text and translation are preceded by an exhaustive commentary, at once mathematical and historical."