Al-Razi (Rhazes) (born in 864 CE) wrote over 200 scientific treatises, many of which had a major impact on European medicine. His best known manuscript is Liber Continens, a medical encyclopedia in which he described his contributions to neurology, focusing on his description of cranial and spinal cord nerves and his clinical case reports, which illustrate his use of neuroanatomy to localize lesions. In this article, Dr Nizar Souayah and Dr Jeffrey I. Greenstein focus on Al-Razi's description of the cranial and spinal nerves and his relevant clinical case reports, which illustrate his understanding of neuroanatomy and the application of his knowledge to clinical practice.