Al-Wafi, containing fifty thousand hadiths along with explanations and commentaries which have been written by its great compiler, the late Fayz Kashani following the hadiths, is reckoned as one of the great sources of hadith. But this book is not regarded as it deserves. Thus the author of the present paper views it from different perspectives and gives a detailed account of this valuable book.The following issues are discussed in this paper: privileges of the book, the author's motive for writing the book, date of its writing, its status in the eyes of Islamic scholars, its manuscript and printed copies, interpretations, annotations and supplements, etc.