The importance of the text which is used as the basis of this book was first recognized in the 1950s by both Claude Cahen and R.B. Serjeant. By good fortune, their individual research efforts were brought together by a mutual friend and colleague and from the 1950s until their deaths in the1990s they worked intermittently on the text in collaboration. Alas, at the time of their deaths, nothing of their scholarly endeavours had been published. This relatively short treatise with its description of the roles of many government officials and its lists of taxes etc., is of immenseimportance to scholars of the medieval Middle East in general and to those of Arabia and the Yemen in particular. It is of tremendous importance as a primary source for the economic history of the thirteenth, fourteenth and early fifteenth century Rasulid state. It is hoped that the facsimileedition which is fully annotated and contains all the necessary introductory material, as well as glossaries and indices, will enable scholars to exploit the contents of this fascinating early fifteenth century document to the full.