This study aims to highlight a treasure of the treasures of the Omani grammatical library, the book of restriction, which is the most extensive literature in his art, deals with the depth and depth of the grammar and some sections of discharge and dictation in ten parts. This letter has been divided into two parts: part of Study and Investigation part; For the first section, I made it in three chapters: First Chapter is concerned with the definition of the author It came in three investigations The first research: His name, title and descent, The second research: the era of the author • Third research: his scientific biography, His elders, His death. Second chapter focused in the study of the book of multiple axes divided between the three researches: The first research: the author's approach in his book of restriction. Second research: the author's position of citation. Third research: the doctrine of the grammatical author and the scholars who inspired them and their statements and the sources on which they were based. Third Chapter: The description of the manuscript and the methodology of the investigation, which included four research • The first research: documenting the name of the book and its relation to its author, the year of its creation and its place. Second research: Description of the written copies approved in the investigation. The third research: the approach of achieving the book. Fourth research: Pictures of the manuscript copies.