One of the most popular monastic authors with a nearly universal spread over time is Isaac of Nineveh, a mystic of the late 7th century, who belonged to the East Syriac Church. This book is dedicated to the doctrine of knowledge, as described in Isaac of Nineveh's discourses, in its double dimension, worldly/philosophical and theological (the former considered to be more discursive/intellectual and the latter intuitive/ experiential) and the rapport established between these two, prolonged in the concept of vision, as the highest form of spiritual experience.