Fayyāz Lāhiji is considered to be one of the most prominent Muslim theologians during the history of Islamic theology; and the best Shia theologian in the recent era. He has been after affirming the true beliefs and resolving the doubts. In the following article, the author provides a full report of Lāhiji’s theological works and explicates their features regarding the structure and the content, especially in some of his eminent works such as Gohar Morād (The Substance of Goal), The Wealth of Faith, and Shavāregh Alelhām. Eventually, some of Fayyāz’s intellectual characteristics are studied.