Who were the key people who taught it or preserved it?

The Prophet ﷺ dictated the revelation to scribes while thousands memorized it. Abu Bakr had it compiled, Uthman standardized it, Zayd ibn Thabit wrote it down — and an unbroken chain of memorizers has carried it since. The hadith scholars and the four imams preserved and taught the rest.

Epicurus and Lucretius in antiquity; Hume, d'Holbach, and Diderot in the Enlightenment; Feuerbach, Marx, and Nietzsche in the 19th century; Bertrand Russell in the 20th; and most recently the 'New Atheists' — Dawkins, Hitchens, Dennett, Harris.

Protagoras and the Greek skeptics; Hume and Kant as the philosophical groundwork; Huxley, who named the position; and figures like Darwin and Bertrand Russell, who described themselves with the word.

The apostles (Peter, John, James); Paul of Tarsus, whose letters are the earliest Christian writings; the Gospel writers; and the church fathers (Irenaeus, Athanasius, Augustine). The ecumenical councils, beginning at Nicaea (325 CE), fixed the creeds.

Moses, the lawgiver of the Torah; the prophets; Ezra the scribe, who re-established Torah reading after the exile; then the rabbis — the Mishnah (c. 200 CE) and the Talmud (c. 500 CE) shaped rabbinic Judaism — and later teachers such as Maimonides.

The Buddha himself; close disciples such as Ananda (who recited the discourses) and Sariputta; the monastic communities that memorized and transmitted the canon; later, thinkers like Nagarjuna for the Mahayana, and the translator-monks who carried the texts to China and Tibet.

The anonymous Vedic seers (rishis); the epic and Gita traditions; philosopher-theologians such as Shankara (non-dualism) and Ramanuja (qualified non-dualism); and generations of bhakti poet-saints. There is no central authority — brahmin lineages and gurus carried the teaching.

The ten Gurus, from Nanak to Gobind Singh. Guru Arjan compiled the scripture (1604); after the tenth Guru, authority passed to the scripture itself — the Guru Granth Sahib — and to the community.

Locke and Voltaire; Jefferson and Madison in America; Holyoake and Bradlaugh in Britain; Jules Ferry and the French republicans. In the 20th century its carriers were mostly jurists, teachers, and constitution-writers rather than preachers.

Renaissance scholars (Petrarch, Erasmus); the Enlightenment philosophes; Felix Adler, founder of Ethical Culture; John Dewey among the first Manifesto's signers; and Julian Huxley, first president of the international humanist union.

Locke, Montesquieu, Adam Smith, Kant, Constant, Tocqueville, and J.S. Mill; in the 20th century, Rawls for the egalitarian wing and Hayek and Friedman for the market wing — one family with rival branches.

Wollstonecraft; Stanton and Anthony; Sojourner Truth; the suffragists, including Pankhurst; Simone de Beauvoir, whose Second Sex (1949) refounded the theory; Betty Friedan; and later bell hooks and Kimberlé Crenshaw, who named intersectionality.

Rousseau and Herder as intellectual sources; Fichte's Addresses to the German Nation; Mazzini, the apostle of national self-determination; Renan, who defined the nation as a 'daily plebiscite.' It was carried mostly by poets, teachers, and states — it has no single canon.