Mirza Tahir Ahmad (مرزا طاہر احمد; 18 December 1928 – 19 April 2003) was the fourth caliph (Arabic: خليفة المسيح الرابع, khalīfatul masīh al-rābi) and the head of the worldwide Ahmadiyya Muslim Community.

[2] Tahir Ahmad also authored many books including, Some Distinctive Features of Islam; Christianity: A Journey from Facts to Fiction; Murder in the Name of Allah, and his magnum opus[3] Revelation, Rationality, Knowledge & Truth.

[6] In 1993 Mirza Tahir Ahmad started an international initiation ceremony to be held every year at the annual gatherings of Ahmadis in which new converts join the community by pledging their allegiance to the Khalifa.

[8] The newly elected Caliph Mirza Masroor Ahmad, as the Khalifatul Masih V, led the funeral prayer on 23 April 2003, attended by over 40,000 people from around the world.

[10] Ahmad wrote a book title Revelation, Rationality, Knowledge and Truth, which was a further development on a talk he gave in Zurich, Switzerland, in 1987.