Until the end of seventeenth century, the literature on Sufism (taṣawwuf) studied and taught in Mauritania (and by extension, Islamic West Africa) was mostly of North African and Middle Eastern origins. With the development of Sufism, particularly following the emergence and spread of Sufi orders (ṭuruq), Mauritanian scholars began to author works on Islamic spirituality. One of these manuals was the Khātimat al-taṣawwuf of Muḥammad al-Yadālī, an 18th century prolific, and perhaps, the most influential scholar of his time and in Mauritania’s Islamic intellectual history. The Khātima is a unique text in style and content. It attracted the attention of numerous scholars, resulting in several commentarial works both in verse and prose. Due to its prominence in the Islamic mystical tradition, the text became, arguably, the most commented upon manual on Sufism in Mauritania (and in Muslim West Africa). Its importance extends to the pivotal manuals of three most influential scholars of the three most popular mystical traditions of West Africa: Sīdī Mukhtār al-Kuntī (d. 1811) of the Qādiriyya, Aḥmadū Bambā (d. 1923) of the Murīdiyya and Ibrāhīm Niasse (d. 1975) of the Tijāniyya orders. However, despite its influence, the work remains largely understudied. Against this background, my paper attempts to open a critical discussion on the Khātima of al-Yadālī. It examines its background, its role in shaping of transformational debates on Sufism and Law in the time and successive centuries of the text, its impact on the works of Sufi scholars, as well as its content. This topic continues the discussions on some of Mauritania’s Islamic intellectual figures and their works, which have not attracted significant scholarly attention.