Wikipedia @ 20: stories of an incomplete revolution: edited by Joseph Reagle and Jackie Koerner, Cambridge, Mass. and London, The MIT Press, 2020, 360 pp., $38 (soft cover), open access edition (PDF), ISBN: 978-026253817-6 (soft cover), ISBN: 9780262360593 (PDF). Issue 4 (2nd October 2021) - Kerrigan, Catherine E