The two volumes of Labarun Hausawa da Makwabtansu, which are frequently mentioned in the footnotes to this book, were published in 1932 and 1933 by the Zaria Translation Bureau which was later to develop into the Caskiya Corporation. It is obvious that they were based on Arabic or Hausa MSS. as well as on oral traditions and in some chapters the original sources are revealed. In others, however, the editors remained silent on the subject. It must be admitted that this omission detracts somewhat from the value of what are otherwise excellent books of reference.

The Provincial Gazetteers, which have also been extensively drawn upon, were compiled just after the First World War and brought out as booklets. They have never been reprinted and are now difficult to obtain. Their historical sections are uneven in quality and by no means free from error but they are always worth consulting and the best of them contain some very valuable material.

The historical notes in the Sokoto, Gwandu, and Kano District Notebooks were compiled by the author himself during the 'fifties in the course of his ordinary administrative touring. Though there were certain drawbacks to this procedure, notably the pressure of other work, it had the great advantage of permitting inquiries to be made on the spot from old gentlemen, repositories of local history, who might otherwise never have been consulted. In both Sokoto and Gwandu it was possible to base these inquiries on the earlier work of P. G. Harris, which was embodied in his revised but unpublished version of the Provincial Gazetteer. Moreover, in Sokoto the task was usually shared with Alhaji Junaidu whose knowledge of local history and genealogy greatly eased and simplified it. The District Notebooks, for those who wish to consult them, are now in the possession of the respective Provincial Administrations and Native Authorities. Similarly, the unpublished MSS. of Mallam. Mustafa and Alhaji Mahmud which are quoted in Chapter Eleven can be consulted through Bauchi Native Authority.

Finally, there is the major contribution made by Alhaji Junaidu which I have acknowledged elsewhere. He is himself a considerable historian and, as Waziri of Sokoto, he has access to many MSS. which have never been published or even translated. He has been good enough to go right through the draft and the author has since consulted him on many doubtful points. Where he has endorsed a judgement or a piece of information, therefore, it has been thought worth while to record the fact specifically in the footnotes.