Muhyiddin Ibn al‐ʿArabi, known as the Greatest Master (
al‐Shaykh al‐Akbar
) is one of Islam's most influential thinkers and prolific writers. He brought the esoteric dimension of Islam to new heights and created a comprehensive system of mystical thought that has infused virtually every Islamic discipline for the past 700 years. After discussing his influence on Islamic scholarship, this chapter will focus on some of his most important ideas: his theory of knowledge, the nature of Being, the concept of Man, and finally, the hierarchy of spiritual people, namely, the saints who are the heirs to the prophets. In this last aspect, Ibn al‐ʿArabi claimed to have been nominated as the Seal of the Saints, a claim that would endure for centuries without being challenged by any other mystic thereafter, earning him his title, the Greatest Master. This study concludes with a discussion on the finality of Ibn al‐ʿArabi's sainthood which is, in his own doctrine, superseded by the Solitary Ones (
al‐afrād
), individuals who are beyond the purview of even the Pole of existence (
al‐qutb
).