Paul Kurtz (born December 21, 1925 in Newark, New Jersey) is a prominent American skeptic and secular humanist. He has been called "the father of secular humanism." He is Professor Emeritus of Philosophy at the State University of New York at Buffalo, having previously also taught at Vassar, Trinity, and Union colleges, and the New School for Social Research.

Kurtz has published of over 800 articles or reviews and has authored and edited over 50 books. Many of his books have been translated into over 60 languages. They include "The Transcendental Temptation," "Forbidden Fruit: The Ethics of Secularism," "The Courage to Become," and "Multi-Secularism: A New Agenda." His published bibliography of writings from 1952 to 2003 runs over 79 pages.

Kurtz founded the publishing house Prometheus Books in 1969. He is also the founder and past chairman of the Committee for Skeptical Inquiry (formerly the Committee for the Scientific Investigation of Claims of the Paranormal (CSICOP)), the Council for Secular Humanism, and the Center for Inquiry. On May 18, 2010, he resigned from all these positions. Moreover, the Center for Inquiry accepted his resignation as chairman emeritus and board member, the culmination of a years-long "leadership transition," thanking him "for his decades of service" while alluding to "concerns about Dr. Kurtz’s day-to-day management of the organization."

William Lane Craig (born August 23, 1949) is an American analytic philosopher, philosophical theologian, and Christian apologist. He is known for his work in the philosophy of religion, philosophy of time, and the defense of Christian theism. One of his most notable contributions to the philosophy of religion is his defense of the Kalām cosmological argument, which is the most widely discussed argument for the existence of God in contemporary Western philosophy. In theology, he has also defended Molinism and the belief that God is, since Creation, subject to time.

Craig has authored or edited over 30 books, including The Kalām Cosmological Argument (1979), The Cosmological Argument from Plato to Leibniz (1980), Theism, Atheism, and Big Bang Cosmology (with Quentin Smith, 1993), Philosophical Foundations for a Christian Worldview (with J.P. Moreland, 2003) and Reasonable Faith: Christian Truth and Apologetics (3d edition, 2008).

Craig received a Bachelor of Arts degree in communications from Wheaton College, Illinois, in 1971 and two summa cum laude master's degrees from Trinity Evangelical Divinity School in Deerfield, Illinois, in 1975, in philosophy of religion and ecclesiastical history. He earned a Ph.D. in philosophy under John Hick at the University of Birmingham, England in 1977 and a Th.D. under Wolfhart Pannenberg at the University of Munich in 1984.

William Lane (6 September 1861 – 26 August 1917) was a journalist, advocate of Australian labour politics and a utopian.

Lane was born in Bristol, England, eldest son of James Lane, from Ireland a Protestant Master Gardener, and his English wife Caroline, née Hall. When Lane was born his father was earning a miserable wage, but later his circumstances improved and he became an employer. The boy was educated at Bristol Grammar School and showed ability, but he was sent early to work as an office boy. Lane's mother died when he was 14 years of age, and at age 16 he migrated to Canada, then to the United States, where he worked first as a printer, then as a reporter for the Detroit Free Press (1881), there meeting his future wife Ann MacGuire. In 1885 they migrated to Brisbane, Australia, where Lane immediately got work as a feature writer for the weekly newspaper Queensland Figaro, then as a columnist for the newspapers Brisbane Courier and Evening Telegraph, using a number of pseudonyms ("Lucinda Sharpe", which some consider to be the work of Annie Lane, William Wilcher and "Sketcher").

Norman L. Geisler (born 1932) is a Christian apologist and the co-founder of Southern Evangelical Seminary outside Charlotte, North Carolina, where he formerly taught. He holds a Ph.D. in philosophy from Loyola University. Geisler is well known for his scholarly contributions to the subjects of Christian apologetics, philosophy, and moderate Calvinism and is the author, coauthor, or editor of over 60 books and hundreds of articles.

Geisler left the Evangelical Theological Society in 2003, after it did not expel Clark Pinnock, who advocates open theism. Geisler testified in McLean v. Arkansas, defending creationism. In the late 20th Century, Geisler entered the Mormon arena. In 1997 he co-authored When Cultists Ask: A Popular Handbook on Cultic Misinterpretation, with Ron Rhodes. 47 of the articles listed in the index, regarded Mormonism. In 1998, he helped put together a book entitled The Counterfeit Gospel of Mormonism, published by Harvest House publishers in Eugene, Oregon. Danel W. Bachman has accused Geisler of plagiarism. In 2009, Geisler co-founded Veritas Evangelical Seminary in Murrieta California. The seminary offers masters degrees in Theology, Apologetics & Divinity. Geisler currently serves as Chair of Christian Apologetics at the school.

James Randi (born Randall James Hamilton Zwinge; August 7, 1928) is a Canadian-American stage magician and scientific skeptic best known as a challenger of paranormal claims and pseudoscience. Randi is the founder of the James Randi Educational Foundation (JREF). Randi began his career as a magician named The Amazing Randi, but after retiring at age 60, he began investigating paranormal, occult, and supernatural claims, which he collectively calls "woo-woo".

Although often referred to as a "debunker", Randi rejects that title owing to its perceived bias, instead describing himself as an "investigator". He has written about the paranormal, skepticism, and the history of magic. He was a frequent guest on The Tonight Show Starring Johnny Carson and was occasionally featured on the television program Penn & Teller: Bullshit!. The JREF sponsors The One Million Dollar Paranormal Challenge offering a prize of US$1,000,000 to eligible applicants who can demonstrate evidence of any paranormal, supernatural or occult power or event under test conditions agreed to by both parties.