Da‘wah or Dawah (Arabic: دعوة‎) usually denotes the preaching of Islam. Da‘wah literally means "issuing a summons" or "making an invitation", being the active participle of a verb meaning variously "to summon" or "to invite" (whose triconsonantal root is د ع ى). A Muslim who practices da‘wah, either as a religious worker or in a volunteer community effort, is called a dā‘ī, plural du‘āt. A dā‘ī is thus a person who invites people to understand Islam through a dialogical process, and may be categorized in some cases as the Islamic equivalent of a missionary, as one who invites people to the faith, to the prayer, or to Islamic life. Da'wah activities can take many forms. Some pursue Islamic studies specifically to perform Da'wah. Mosques and other Islamic centers sometimes spread Da'wah actively, similar to evangelical churches. Others consider being open to the public and answering questions to be Da'wah. Recalling Muslims to the faith and expanding their knowledge can also be considered Da'wah.

Yusuf Estes (born in 1944) is an American Muslim preacher and teacher who converted from Christianity to Islam in 1991. He was a Muslim Chaplain for the United States Bureau of Prisons through the 1990s. He was a Muslim Delegate to the United Nations World Peace Conference for Religious Leaders held at the U.N. in September 2000.

Active in Islamic missionary work in the United States, Estes is often featured as guest presenter and keynote speaker at various Islamic events as well as frequently appearing on various Islamic satellite TV channels. Estes takes a dim view of today's public school system in the United States for any children, and highly recommends schools where they might receive a religious education combined with more advanced scholastic education.

Yusuf Estes was born in Ohio, and was raised in Houston, Texas in a Anglo-Saxon Protestant family. From 1962 to 1990, his career was in the music, entertainment and marketing fields. He also taught music and served as a music minister. He owned several musical instrument companies including the Estes Piano and Organ Company. He produced and directed live entertainment programs in the United States from the mid 1960s until his last endeavor for cable TV in Florida, entitled 'Estes Music Jamboree'.

Muhammad Ali (born Cassius Marcellus Clay, Jr.; January 17, 1942) is an American former professional boxer, philanthropist and social activist. Considered a cultural icon, Ali was both idolized and vilified.

Originally known as Cassius Clay, Ali changed his name after joining the Nation of Islam in 1964, subsequently converting to Sunni Islam in 1975, and more recently practicing Sufism.^{[clarification needed]} In 1967, three years after Ali had won the World Heavyweight Championship, he was publicly vilified for his refusal to be conscripted into the U.S. military, based on his religious beliefs and opposition to the Vietnam War. Ali stated, "I ain't got no quarrel with them Viet Cong... No Viet Cong ever called me nigger" – one of the more telling remarks of the era.

Widespread protests against the Vietnam War had not yet begun, but with that one phrase, Ali articulated the reason to oppose the war for a generation of young Americans, and his words served as a touchstone for the racial and antiwar upheavals that would rock the 1960s. Ali's example inspired Martin Luther King Jr. – who had been reluctant to alienate the Johnson Administration and its support of the civil rights agenda – to voice his own opposition to the war for the first time.