||The infinite has been an important topic in many branches of philosophy (and neighboring disciplines), including metaphysics, epistemology, the philosophy of physics, the philosophy of religion, and ethics. But since at least the 19th century, when B. Bolzano, G. Cantor, R. Dedekind, and others made crucial contributions, the most central discussions about the infinite have taken place in the philosophy of mathematics and logic. For a rich, historically grounded, but also opinionated introduction, see A.W. Moore, The Infinite (2nd edition, Routledge, 2001). Many classic articles on the topic are contained in A.W. Moore, ed., Infinity (International Research Library of Philosophy, Dartmouth, 1993). For a more basic introduction, see P. Zellini's A Brief History of Infinity (Penguin, 2004), and on the mathematical side, I. Stewart's Infinity. A Very Short Introduction (Oxford University Press, 2017) and E. Cheng's Beyond Infinity (Basic Books, 2017). Finally, for advanced logico-mathematical aspects, see A. Kanamori, The Higher Infinite (2nd ed., Springer, 1994).