21 Lessons for the 21st Century is a book written by bestseller Israeli author Yuval Noah Harari and published in August 2018 by Spiegel & Grau in the US and by Jonathan Cape in the UK and dedicated to his husband, Itzik.

Having dealt with the distant past in Sapiens: A Brief History of Humankind (2011) and with the distant future in Homo Deus: A Brief History of Tomorrow (2016), Harari turns in 21 Lessons his attention to the present. In a loose collection of essays, many based on articles previously published, he attempts to untangle the technological, political, social, and existential quandaries that humankind faces.