Abu Bakr al-Razi (865-926 CE) was a Persian doctor, philosopher, chemist, and humanitarian who, despite his agnosticism and belief that all religions were created by man, was well known and beloved in the early Muslim world.

A system of philosophy developed in India around 600 BCE and named after its founder, Carvaka. Although virtually no writings from its followers have survived, was known to emphasize rational thought and skepticism over and against the mystical and supernatural.

An organization that aims to “foster a secular society based on science, reason, freedom of inquiry, and humanist values.” Founded by Paul Kurtz and headquartered in Amherst, New York, CFI has branches across the United States and around the world.

Richard Dawkins (1941–) is a British evolutionary biologist who became a well known public face of the “New Atheists” movement that gained ground during the early 21st century. Dawkins’ most famous works include The Selfish Gene (1976), The Blind Watchmaker (1986), and The God Delusion (2006).

Greg Epstein (1977-) is the Humanist Chaplain at Harvard University, a leader in the founding of the Harvard Humanist Community Project, and author of Good Without God: What a Billion Nonreligious People Do Believe (2009). In 2005, Epstein was ordained as a Humanist Rabbi by the International Institute for Secular Humanistic Judaism and has earned degrees from the University of Michigan and Harvard Divinity School.

The Ethical Culture Movement was founded in the late 19th century by Felix Adler and represents one of the first successful attempts to organize a community around secular values. Today, there are a network of Ethical Societies which stem from the Ethical Cultural Movement; in the United States, the American Ethical Union is a national organization with chapters around the country.

Freethought is a philosophical worldview that maintains that all matters can be a topic of conversation and opinions should not be formed from tradition or dogma but rather from logic and reason.

Sam Harris (1967-) is a prolific author and co-founder and CEO of Project Reason. His most well known books include The End of Faith (2004), Letter to a Christian Nation (2006), The Moral Landscape (2010), and Free Will (2012). Harris was educated in philosophy at Stanford University and has a PhD in Neuroscience from UCLA.

Christopher Hitchens (1949–2011) was a British American author and journalist and one of the most well known public faces of the “New Atheists.” He was an outspoken critic of religion and authored God is Not Great: How Religion Poisons Everything (2007).

Humanism is a belief system that values reason, compassion, and hope. Emphasis is placed on human concerns and that which can contribute to human flourishing. Dogmas or creeds that in any way impede these foci are disregarded and humanity is thought to be responsible for its own destiny.

The Humanist Community Project is an initiative of the Humanist Chaplaincy at Harvard that seeks to research and resource the Humanist, skeptic, atheist, and not religious communities of America.

The Humanist Manifestos are a series of statements which outline the core beliefs of the Humanist movement. The first, A Humanist Manifesto (1933) was primarily written by Raymond Bragg with 34 co-signers and published in the May/June 1933 issue of the New Humanist. Unlike subsequent manifestos, A Humanist Manifesto refers to Humanism as a “religious movement” that would transcend other religious systems that were steeped in the supernatural. Humanist Manifesto II (1973) was written by Paul Kurtz and Edwin H. Wilson and published in the September/October 1973 issue of The Humanist. It was intended as an updated version of the first manifesto and addressed specifically a few of the political and social events of the day such as racism, birth control, and weapons of mass destruction. Humanist Manifesto III is the subtitle of the 2003 statement by the American Humanist Association titled Humanism and Its Aspiration. The document echoes, in brief, many of the same themes as its predecessors.

Robert Ingersoll (1833–1899 CE) was a veteran of the American Civil War and famed orator whose defense of agnosticism came during “the golden age of freethought.”

Multivalent terms that often are used to describe people (or their worldview) who reject the practices, dogma, and creeds of established religious traditions. Some people, on the other hand, may identify as Humanist and also consider this either a belief system unto itself or a complement to a theistic worldview.

Rationalism is a philosophical tradition that understands reason to be the foundation for all knowledge. Empiricism, or the idea that all knowledge comes from sense experience, is key to rationalism.

The Reason Rally was held on March 24, 2012 to support secularism and religious skepticism. The march and program that took place on the National Mall in Washington, D.C. was sponsored by several major secular and atheist organizations. According to reports from The Atlantic, 20,000 people attended the event.

Religious humanism draws upon the rites and communal aspects of religion while maintaining secular values and a rejection of theism and the supernatural. Oasis, a growing community in Houston, Texas is one example of “atheist churches” in the United States.

Eugene Wesley “Gene” Roddenberry (1921-1991 CE) was the creator of the immensely popular Star Trek, a franchise that includes seven television series and ten movies. Roddenberry, a Humanist, expressed through his life’s work a hopeful view of humanity’s future.

Ernestine Rose (1810-1892 CE) was an abolitionist and atheist feminist, the daughter of a Polish rabbi. At the age of sixteen she won a case against her father who insisted that she marry a man he chose for her; after the ruling, she left Poland and lived in England then settled in the United States where she established herself as well known and major intellectual figure in the 19th century struggles for women’s rights.

Secular humanism is the belief that ultimate values reside within the human individual and possess no supernatural origin; it has been shaped by Enlightenment rationalism, Darwinian science, and later by Freudian and post-Freudian psychology. The humanist movement gained currency in the United States during the late nineteenth century and was expressed through the programs of the Ethical Culture Society and the nontheistic wing of Unitarianism; was popular among the intelligentsia. In the twentieth and 21st century, the Humanist movement has produced three “Humanist Manifestos” which were issued in 1933, 1973, and 2003.

The Secular Student Alliance is a network of campus-based student organizations that seek to promote “the ideals of scientific and critical inquiry, democracy, secularism, and human-based ethics.”

Skeptics are people who question religion, religious tenets, or other truth claims.

Representative Pete Stark (1931-) is the first openly atheist member of the United States Congress. His beliefs became known in 2007 when he responded to a Secular Coalition for America questionnaire, a stance he publicly announced that same year. Stark (D-CA) was named Humanist of the Year in 2008 by the American Humanist Association. He worked with the AHA to introduce a Congressional bill that would recognize February 12, 2011 as “Darwin Day,” in honor of Charles Darwin.

Chris Stedman (1987-) is an openly gay atheist, interfaith activist, and Assistant Humanist Chaplain at Harvard University. He is founder of the blog Non-Prophet Status and is a regular contributor to The Huffington Post. Stedman is author of the 2012 memoir Faitheist: How an Atheist Found Common Ground with the Religious.

A groundbreaking work on evolutionary biology published by Charles Darwin in 1859. It became—and remains—controversial among those who maintain a literal translation of the biblical seven-day creation myth.