Muhammad bin Husayn bin Abdul Samad, called Baha' al-Ddin al-Harithi al-'Amili was born in Ba'labak in 953 H/1547CE. He died in Isfahan in 1031 H/1622 CE. He wrote in many subjects such as mathematics, astronomy, the sciences of religion, the arts, and language.
Among his scientific left books we find Kitab khlusat al-hisab (The conclusion of arithmetic). The book comprises an introduction and ten parts. It deals with the basic arithmetical operations such as addition, subtraction, multiplication, and division, and also with the properties of numbers, addition in mathematical series, algebra and equations, the areas of geometrical plane figures, the volumes of regular solids and other subjects.