There is a Great to demand for book for Ar Rahnu for several reason, firstly because this concept relatively new in islamic economics. secondly this book is not exclusively of this time but all this time. the ideas in this book are always fresh and new. the study on the fiqh of ar rahnu is the study of the foundation of ar rahnu operation. Thirdly, our explanation on the institusional aspect of ar rahnu might help to explain the role of law, of governance, of organization, and of sociology establishing an institution like ar rahnu.