Mirza Tahir Ahmad (Born December 18, 1928 in Qadian, died April 19, 2003 in London) was Khalifatul Masih IV., head of the Ahmadiyya Muslim Community. He was elected to this office in 1982, the day after the death of his predecessor, Mirza Nasir Ahmad. He was the son of Mirza Basheer-ud-Din Mahmood Ahmad, the second Caliph and was the half-brother of Mirza Nasir Ahmad, the third Caliph. He graduated from Jamia Ahmadiyya (Theological Academy) at Rabwah, followed by higher education in Lahore at the University of Punjab, and London at the University of London School of Oriental and African Studies. In 1974 he was also nominated the member of the Ahmadiyya delegation which appeared in the Parliament of Pakistan to defend the beliefs of Ahmadiyya Community. The Parliament after thorough investigation by their leading scholars, declared Ahmadi's to be non-Muslims.
Mirza Tahir Ahmad was the fourth successor of Mirza Ghulam Ahmad, and was elected to his office as Khalifatul Masih in 1982.
Mirza Tahir Ahmad returned to Qadian (the original centre of the community) in 1991 for the 100th annual gathering of the community; which was the first time an Ahmadiyya Khalifa had returned to Qadian since the second Khalifa left in 1947. He is perhaps best known for his Question & Answers Sessions. The community experienced structural and financial growth during his time. He launched, in 1994, the first Muslim satellite television network by the name of Muslim Television Ahmadiyya.
Mirza Tahir Ahmed was born on 18 December 1928. He obtained his early schooling at Qadian and joined the Government College Lahore in 1944, a few months after the death of his mother (Maryam Begum). After graduating with distinction from the Ahmadiyya Missionary College Rabwah, he obtained his honours degree in Arabic from the University of Punjab, Lahore.
In 1955, he visited England for the first time with his father, who advised him to remain there to improve his knowledge of the English language and acquaint him with European social habits. He studied for 2 and a half years at SOAS, University of London. He returned in December 1957 without achieving any degree. Instead, during his stay in London, he visited different parts of England, Ireland, Scotland, Wales and also some parts of Western Europe.
Upon his return in 1957 he married Asifa Begum, and was appointed the vice president of the newly founded Waqf-e-Jadid foundation. The main task of the Waqf-e-Jadid was to educate the community members living in rural areas of Pakistan. Due to his work in this foundation, Mirza Tahir Ahmad acquired vast experience with Ahmadies from various fields of life across the Indian sub-continent. It was as part of his work in Waqf-e-Jadid that he also started treating poor people with homeopathic medicines (see Homeopathy) and acquired a lot of experience in this field.
During the parliamentary investigations regarding the status of the community a delegation comprising of 5 members was sent under the leadership of the third Caliph MirzaNasir Ahmad. This delegation included the Caliph, Abu-al-Atta Jalandhari, a well known Ahmadi scholar, Dost Mohammad Shahid, official historian of the community, Mohammad Ahmad Mazhar, a well known lawyer, and Mirza Tahir Ahmad.Among the panel Mirza Tahir Ahmad was the youngest menmber which shows the extent of knowledge he possessed of the community .After several days of discussions, the Ahmadiyya Community was declared Non-Muslim by the Pakistani National Assembly. This has remained their constitutional and legal position in Pakistan to this day.
The Jamaat's electoral college elected Mirza Tahir Ahmed as the fourth successor to Mirza Ghulam Ahmad and head of the community on June 10, 1982.
After taking office, Mirza Tahir Ahmad worked to restore the Community with a new passion. The Anti-Ahmadiyya ordinance, passed by General Zia ul Haq's government on 26 April 1984, compelled him to leave Pakistan immediately, details of this journey can be found in the book A man of God by Ian Adamson. He decided to come to England where he established his base during his years of exile.
Mirza Tahir Ahmad died from heart failure in 2003. He was buried at community property "Islamabad" in Tilford, Surrey. After his death, Mirza Masroor Ahmad was elected as the fifth Head of the Ahmadiyya Muslim Community.
Return to India
In 1991 Mirza Tahir Ahmad returned to India to attend the hundredth Annual Gathering of the Ahmadiyya Muslim Community, India. This was the first time that a Caliph of the Ahmadiyya Muslim Community had visited India since partition in 1947 and exile to London.
Muslim Television Ahmadiyya
One of the achievements of his life was the initiation of the Muslim Television Ahmadiyya (MTA). This satellite based channel was started in 1993 with a weekly one hour program, broadcasting the Friday sermon of the head of the community. The main purpose of the channel at that time was to establish direct contact with the main body of Ahmadies especially in Pakistan. In 1994, the station was established and also in 1996 the area of broadcasting with the start of round the clock broadcasting. It now includes full 24-hour services all over the world and consists of three channels. Important events of the community are televised in most major languages of the world. Mirza Tahir Ahmad had to give long hours of his already constrained time to start the transmissions.
Another added feature to the community activities was the international initiation ceremony, which was started by Mirza Tahir Ahmad during the annual convention of the community in Surrey, BC. The ceremony was broadcast live across the world and the new converts join the community by pledging their allegiance to the Khalifa. The head of the community accepts the oath of alligence. The International Baiat was started by Mirza Tahir Ahmad in 1993 along with a scheme of propagation.
Revelation, Rationality, Knowledge & Truth
Mirza Tahir Ahmad wrote among many others, a book named “Revelation, Rationality, Knowledge & Truth” which was a further development on a talk he gave in Zurich, Switzerland. There, in 1987 Professor Karl Henking, Professor of Ethnology, University of Zurich invited the Head of the Worldwide Ahmadiyya Community to deliver a lecture. On Thursday, the 14 June 1987 at 8.15 p.m., the proposed lecture was delivered under the title Rationality, Revelation, Knowledge, Eternal Truth. The students, evidently intrigued by the title, thronged Oule (the great auditorium) which became filled to capacity so that additional arrangements had to be made in another hall with provisions for relaying the proceedings through television screens and loudspeakers. The lecture was developed further in its subject matter and material over the period of almost 10 years and finally published in the form of a book, entitled, “Revelation, Rationality, Knowledge & Truth”.
In this magnum opus Mirza Tahir Ahmad has the distinction of being the only religious leader to date to provide a scientific rebuttal to the Godless theories of the eminent biologist Richard Dawkins. He also argued that Socrates was a prophet of the ancient Greeks. The apparent prophetic qualities of Socrates are indeed a subject for academic debate . The constant reference to the oracle and how it performs the active function of a moral compass by preventing him from unseemly acts could easily be taken as a reference to - or substitute for revelation. Similarly, Socrates often refers to God in the singular as opposed to the plural 
Mirza Tahir Ahmad was a world-renowned homeopath. He took interest in the books collected by his father Mirza Basheeruddin Mahmood Ahmad. After trying a couple of remedies for his own migraine and his wife's long-standing ailment, he was fascinated by the efficacy of homeopathic remedies. Before his Caliphate, he was already treating thousands of visitors at the annual conventions. After his election, his expertise was called upon by Ahmadis all over the globe through letters, as well as by leading doctors in London. He embarked upon a program of training others through classes televised on MTA International. These lectures were later compiled in an excellent book (below). Mirza Tahir Ahmad said "homeopathy will replace all modern medicine - except surgery" (Interview 1996)
Writings, Speeches and Question-Answer-Sessions
- Revelation, Rationality, Knowledge & Truth – Comprehensive book by Khalifatul Masih IVrh that examines the relationships between science, philosophy and religion. (English  | Arabic )
- Sawaney Fazl - E - Omer - Official Biography of Mirza Basheer-ud-Din Mahmood Ahmad, the second Caliph of the Ahmadiyya Muslim Community.
- An Elementary Study of Islam  (Book)
- Gulf Crisis and The New World Order (English | Arabic) 
- Christianity - A Journey from Facts to Fiction (Book)
- Murder in the Name of Allah (Book)
- Zahaqal Baatil (Urdu |Arabic  |English )
- Reality of punishment of apostasy in Islam (Urdu) 
- Khatame-Nabbuwat (Urdu pdf) 
- Homeopathy (Book)
- Some Distinctive Features of Islam (Book)
- Islam's Response to Contemporary Issues (English  |Urdu ) (Book)
- Kalam-e-Tahir (Poetry Book)
- Unity of God 
- Hazrat Imam Mahdi (as) 
- Future of Western Society (Majlis Irfan) 
- Natural Disasters (Majlis Irfan) 
- Prophet's Guide Mankind to God (Majlis Irfan)
- Investment, Interest and Islam (Majlis Irfan)
- Gulf War: Quotations from Sermons 
- Natural Disaster or Divine Punishment [Part I |Part II |Part III |Part IV |Part V 
- Life After Death (Majlis Irfan) 
- Faith and Reality (Majlis Irfan) 
- Lord Krishna and Jesus Christ (Majlis Irfan) 
- The Journey Within (Majlis Irfan) 
- Attainment of Inner Peace (Majlis Irfan) 
- Inspiration, Revelation, and Belief (Majlis Irfan) 
- The Philosophy of Revival of Religion
- Universal and Moral Values, Politics and World Peace 
- Finality of Prophethood (English pdf) 
- With Love to the Muslims of the World - The Ahmadiyya Perspective
- The Philosophy of Revival of Religion 
Family, Marriage and Children
Mirza Tahir Ahmad was the Grandson of Mirza Ghulam Ahmad and the son of Mirza Basheer-ud-Din Mahmood Ahmad, the second Caliph of the Ahmadiyya Community, from his wife Syeda Maryam Begum. His mother was daughter of Syed Abdul Sattar Shah, a companion of Mirza Ghulam Ahmad.
Mirza Tahir Ahmad married Asifa Begum in 1957. Asifa Begum died on April 3, 1992. His marriage bestowed him 5 daughters, one of whom died in infancy. His daughters are Shaukat Jehan, Faiza, Yasmin Rehman Mona, Tooba and one who died in infancy. He had no sons but later he took the upbringing and educational training of a boy, Bashir.