Synopsis There are many books dealing with this specialized subject, but when the author engaged himself in this work he found from his study and experience that the Conversion Tables in circulation are not very comprehensive and suffered mainly from two shortcomings-inaccuracy and intricacy. His work tries to rectify both. This Compendium consists of three main parts: Part I, illustrates the method of synchronizing Hijrah datres with the Gregorian dates from 506 A.D. (120B.H.) onwards. Part II, deals with the computation of the Pre-Hijrah dates from 60 B.H. to 1 B.H. (564-621 A.D.), and Post –Hijrah dates from 1 A.H. (622 A.D.) onwards into Julian and Gregorian Calendar dates with the help of the formulas. Part III, outlines the mathematical method of calculation of Gregorian dates from 641 B.H. to 1 B.H. (1 A.D. – 621 A.D.), and the Post-Hijrah dates from 1 A.H. (622 A.D.) ONWARDS INTO Julian and Gregorian Calendar dates, and can also show the day of the week of any date of Pre-Hijrah, Post-Hijrah, Julian and Gregorian Calendars with the help of infinite Calendars. This Compendium of the conversion of the Muslim and Christian dates is an encyclopaedic work yet compiled and has been prepared after considerable study and labour with hope that it will be useful to students and scholars, as well as laymen alike.