*Ars Conjectandi*is not a book that non-statisticians will have heard of, nor one that many statisticians will have heard of either. The title means ‘The Art of Conjecturing’ – which in turn means roughly ‘What You Can Work Out From the Evidence.’ But it is worth statisticians celebrating it, because it is the book that gave an adequate mathematical foundation to their discipline, and it was published 300 years ago this year.

Significance Magazine is published for the Royal Statistical Society, American Statistical Association and Statistical Society of Australia by Oxford University Press.