Sadi established a style of prose and poetry by writing GolestÁ n in 656 AH which has so far had many followers. JowainÐ ’ s NegÁ restÁ n, was written in 735 AH 79 years after Sadi's GolestÁ n. This book, after the Majd KhafÐ ’ s Rowzeh khold, may be considered as the second and nearest to the era of writing GolestÁ n. NegÁ restÁ n is a book of moral teachings and mysticism, written in imitation of Sadi's GolestÁ n. The book consists of seven chapters: on Guardianship and Virtue; on Noble Characters; on Good Communication; on Love and Affection; on Preaching and Conscience; on Grace and Mercy; and Miscellaneous Benefits. Although its prose is not as great as GolestÁ n, it is filled with historical points and information. This study deals firstly with the investigation of the manuscript of Moein al-DÐ n JowainÐ ’ s NegÁ restÁ n and secondly with Moein al-DÐ n JowainÐ and his book, based on biographies and early and modern literature books. The authors of the present paper first give an account of the author Moein al-DÐ n JowainÐ , then come up with existing information about his name and nickname, pseudonym, birth and death, professors and endorsers of works; and his religious character and beliefs. They then classify, analyze and verify the available data. Based on the textual evidences, they review topics such as: NegÁ restÁ n’ s attribution to the author, the writing of NegÁ restÁ n, why book named "NegÁ restÁ n", pseudonym of books, articles and book themes, genre of books, scientific status of NegÁ restÁ n.