This chapter presents original translations on the classification and symptom manifestations of neuropsychiatric disorders from Abūl-Hasan ‘Alī ibn Sahl at-Tabarī’s Arabic text Firdaus al-Hikma (The Paradise of Wisdom), the first original composition in the Islamic medical tradition. Arabic medicine has been characterised as a corpus of scientific texts translated into Arabic, mostly from Greek sources, starting from the eighth century [1]. It inherited the Galenic system of pathology, understood as the disturbed equilibrium of the four humours (blood, mucus, yellow bile and black bile [2]) and acquired an Islamic character with the spread of Islam in 622 CE beyond the Arabian peninsula [3]. Greek scientific texts from the Hellenistic, Roman and late Antiquity eras were translated into Arabic in an ambitious state project sponsored by the Abbasid caliphate in Baghdad from the eighth to tenth centuries [4]. For example, the ninth-century Abbasid caliph al-Mutawakkil employed as his court physician a Nestorian Christian named Hunayn ibn Ishāq whose team translated the medical compendia of Hippocrates and Galen, the philosophical treatises of Plato and Aristotle, and mathematical works of Euclid and Archimedes [5]. The caliph Harūn ar-Rashīd established a hospital in Baghdad in 805 CE, and 34 more hospitals arose throughout his dominion within two decades [6]. As Islam spread into the Iberian peninsula, Arabic became the language of science into which Greek and Syriac texts were translated in academic centres at Toledo and Córdoba for eventual diffusion into Europe [7].