Field Marshal Ayub Khan kept his diary from September 1966 to October 1972, a very active period in Pakistan's history which included Ayub's yielding of the presidency to Yahya Khan and the period of Yahya's rule that saw the ending of the unified state of Pakistan with the independence of Bangladesh, and also the replacement of Yahya by Zulfiqar Ali Bhutto. Ayub's diary presents his views and interpretations of the events of the period for which it was kept. The diary was discontinued when declining health prevented him from continuing. In his introductory note he stated that the diary must be withheld from publication for an unspecified time as his comments may contain sensitive material. Accordingly, the diary has been withheld from publication for 30 years, and although it does include material that is critical of many personalities and events. Ayub also stated that the material contained in the diary might serve as the basis of a sequel to his book, Friends, not Masters. The editor has included additional notes that pertain to many of the persons and events of this turbulent time in Pakistan's history. The diary will therefore provide essential material for those studying the period, and also provide a means for those who lived through theses times to understand the views of Ayub.