As the primary scholarly reference for Western researchers delving into the Quran, Islamic studies, and the lives of prophets and imams, the Encyclopaedia of Islam is invaluable. Nonetheless, a thorough evaluation of the articles and research contained within is essential to determining their credibility and scholarly consistency. Studying and examining the works of Orientalists about the Qur'an, Islamic sciences, and teachings is an undeniable thing for Muslims. Considering the position of Imam Ali (AS) as the first Imam of the Shias and his superior position in the beliefs of the Shias, orientalists have studied various aspects of his life in their studies and have presented two completely different points of view: A positive and optimistic perspective resulting from Western scholars' study of authoritative texts that explains and praises His scientific approach to interpretation, law, politics, jurisprudence, rhetoric, and more. The negative perspective resulting from a biased viewpoint and the failure to utilise authentic Muslim sources ultimately leading to skeptical opinions regarding the exalted character of Imam Ali (AS). The majority of the articles in this book stem from the intellectual efforts of Western researchers, but regrettably, their lack of access to reference sources has resulted in serious errors. In this research, using the library method through an analytical and critical approach, we will examine the work of Robert Gleave, an impartial and positive orientalist, about Imam Ali (AS) and then examine and criticize the doubts raised by him. In conclusion, the results of the research indicated that Orientalists' lack of access to authentic Islamic sources, coupled with their prejudice and partiality, led to their inability to correctly introduce this Imam to Western society.