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.

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.

Katheryn Elizabeth Hudson (born October 25, 1984), known by her stage name Katy Perry, is an American singer, songwriter and actress. Perry grew up with gospel music, and during her first year of high school she pursued a music career as Katy Hudson, releasing her first studio album called Katy Hudson which failed to chart. She recorded a solo album later, which was never released. After signing with Capitol Music Group in 2007, her fourth record label in seven years, she adopted the stage name Katy Perry.

She first gained recognition with the release of her first mainstream album, One of the Boys in 2008, which spawned three Billboard Hot 100 top-ten songs—"I Kissed A Girl", "Hot n Cold" and "Waking Up In Vegas". Perry supported the album with her Hello Katy Tour. In 2010, her third studio album, Teenage Dream (2010), which topped the Billboard 200 chart, and spawned five number one singles—"California Gurls", "Teenage Dream", "Firework", "E.T." and "Last Friday Night (T.G.I.F.)"—Teenage Dream was the only album (after Michael Jackson's Bad)—to do so, and the first female in history to achieve this milestone. She embarked on the California Dreams Tour, which grossed nearly $60 million worldwide. Perry re-released the album under the name of Teenage Dream: The Complete Confection on March 26, 2012, and the re-release has already spawned the number-one single "Part of Me".