Uncertainty is everywhere. It lurks in every consideration of the future – the weather, the economy, the sex of an unborn child – even quantities we think that we know such as populations or the transit of the planets contain the possibility of error. It’s no wonder that, throughout that history, we have attempted to produce rigidly defined areas of uncertainty – we prefer the surprise party to the surprise asteroid. Here Ian Stewart explores the history and mathematics of uncertainty. Touching on gambling, probability, statistics, financial and weather forecasts, censuses, medical studies, chaos, quantum physics, and climate, he makes one thing clear: a reasonable probability is the only certainty.