This study deals with ʻAlāʼ ad-Dīn al-Ĥujandī’s life and his book titled al-Quśārā fī as-Śarf which is a summary on the topics of Śarf. The first section of this study contains information about ʻAlāʼ ad-Dīn al-Ĥujandī’s life, his personality as a scholar, his works and his students. The next section is comprised of the naming of al-Quśārā fī as-Śarf, whether or not it was authored by al-Ĥujandī, its contents, the studies covering it, possible evaluations about the book, its existing manuscripts, the main manuscripts and method used for the textual criticism. The last section contains the book’s criticism. The book was regarded as important by language scholars at the time of writing and later on and was commented on many times. In this criticism, parts that were difficult to understand have been clarified with the help of those commentaries. The aim of this study is to give information about ʻAlāʼ ad-Dīn al-Ĥujandī who stood out with his knowledge in the areas of Arabic language and fiqh, and to fill the void in this space with the analysis and criticism of his al-Quśārā which helped students learn the matters of śarf in an easy manner.