 For Avicenna, the proper subject of natural philosophy, in its broadest or most general sense, is body insofar as it is subject to motion. Beyond general physics (al-samāʿ al-ṭabīʿī), the physical sciences are further divided into various special sciences distinguished according to either the kind of motion investigated or the kind of body treated. While Avicenna himself does not explicitly identify his decision procedure for dividing the special natural sciences, it is evidenced in the way that he divides up the books of his monumental encyclopedia of philosophy and the sciences, The Cure (al-Shifāʾ). For example, his book On the Heavens and Earth (Fī l-Samāʾ wa-l-ʿālam) from The Cure generally treats rectilinear and circular motion; On Generation and Corruption (Fī l-Kawn wa-l-fasād) deals with change as it occurs in the Aristotelian category of substance, whereas On Actions and Passions (Fī l-Afʿāl wa-l-infiʿālāt) concerns how bodies are affected and affect one another with respect to, for example, the primary qualities of hot-cold and wet-dry, which they possess. Avicenna distinguishes additional special natural sciences according to the specific sort of body being considered, namely, whether the body is inanimate—generally the subject matter of Meteorology (al-Maʿādin wa-l-āthār al-ʿulwiyya)—or the body is animate—the subject of psychology (literally, the science of the soul or animating principle). Avicenna further divides the study of living bodies into general psychology (ʿilm al-nafs), botany (al-nabāt) and zoology (ṭabāʾiʿ al-hayawān). The focus of the present study is limited primarily to Avicenna’s general natural philosophy, although at times the discussion is supplemented with developments in the special physical sciences. 