How do we know what's true? The bestselling author of The Rules of Contagion mines two millennia of knowledge to find out

A FINANCIAL TIMES BOOK OF THE YEAR 'Insightful, absorbing and entertaining' TLS 'Brilliant' ALEX BELLOS 'Illuminating' DAILY MAIL 'The case for better evidence in post-evidence times' FINANCIAL TIMES 'Profound and utterly absorbing' CHRIS VAN TULLEKEN How far would you go in your search for certainty? And once you get there, how do you convince others? From the medieval Islamic world to the recent pandemic, scientific progress has relied on different methods of establishing fact from fiction. Today, in the face of ever-increasing disinformation, how we prove things - to ourselves and others - has never felt more urgent. But there is far more to proof than axioms, theories and scientific laws: when demonstrating that an experimental medical treatment works, persuading a jury of someone's guilt, or deciding whether to trust a new type of financial transaction, weighing up evidence is rarely simple. Bestselling author, statistician and epidemiologist Adam Kucharski ranges across science, politics, philosophy and economics to explore how truth emerges - and why it falters.

"Adam Kucharski explains how certainty, even in math, can be an illusion" - New York Times

"As misinformation and disinformation run riot, including in health and wellness, the concepts of truth and certainty have never felt more slippery. Kucharski explains how we know things and to what level of certainty, and how to hone our own decision-making. Engaging and uncondescending" - FT Best Books of 2025

"Excellent... a great guide to embracing this complexity in truth-seeking" - New Scientist

"A fascinating tour of the history of what has counted as proof ... we enter a wild realm where intuitions break down completely" - Wall Street Journal

"Illuminating ... This is a serious book by a serious person. It's full of gnarly theorems and concepts. But it's also a virtuosic look at the varied and sometimes amusing ways human beings have over the centuries used their intelligence to make sense of the world" - Daily Mail

"Insightful, absorbing and entertaining, Proof traces the rise of humankind's conscious but fallible rationality from the time of the ancient greeks to the rise of modern epidemiology" - TLS

"The case for better evidence in post-evidence times...a slice of the history of mathematics demonstrating that even logic can't deliver absolute truth" - Financial Times

"Shows how proof is more elusive than we realise, whether in law, science, policy or math" - Bloomberg

"Kucharski explains why getting at the truth of just about anything is incredibly hard. There's fascinating technical detail here, and a moral: the more we appreciate how hard proof is to come by, the better we can bridge the widening gulf between experts and sceptics" - New Scientist

"It's a difficult task to know anything for sure, but in Proof, Adam Kucharski explores what it even means to know, to believe and to convince. It's fascinating, it's insightful and, best of all, it's accessible." - B&N Reads

"Praise for The Rules of Contagion: 'An eye-opening read, a worthwhile book" - Sunday Times

"A clear, calm, historical overview of the mathematical ideas at the forefront of our pandemic response, where they came from and how well they stand up when you put them to the test." - Guardian

"Charts the history of this now-pivotal science, from its origins in understanding the spread of malaria, to its central role in predicting the dissemination of everything from diseases to fake news." - Economist

"Astonishingly bold...Kucharski has pulled off the extraordinary trick of shining the brightest light on this unseen, menacing, but ultimately beatable, enemy." - Daily Mail

"As a prominent UK epidemiologist, Kucharski became a hero to some and villain to others for his evidence-based views on the Covid-19 pandemic. The experience led him to write this excellent book about proof, uncertainty and - very importantly - how to communicate scientific evidence to the public as clearly and convincingly as possible" - FT Best Summer Books of 2025