A Dialogue Concerning Heresies, first published in June 1529, was the earliest of six interconnected vernacular treatises against the Reformation, culminating in 1533 in The Answer to a Poisoned Book. This controversial broadside, totalling an astonishing one million words, was the most sustained literary effort of More’s life, and was produced in just five years, for three of which he held the highest secular office in the land as lord chancellor of England, and was busy as a zealous heresy-hunter.

These books have had few admirers. Charles Lamb thought them informed by a wit and malice ‘hyper-satanic’, Richard Marius saw in them a dispiriting parade of ‘ferocity and dreary dullness’ and Alistair Fox ‘a pattern of progressive deterioration’ as ‘dialogue gives way to debellation, self-control leads to loss of proportion and perspective, candour is replaced by dishonesty, and charity is displaced by violence’. The sustained polemic in these works, against heretics in general and the Protestant preachers burned in the early 1530s in particular, has alienated even well-disposed commentators. In a sympathetic recent discussion of the Dialogue, James Simpson nevertheless deplored the ‘heartless mockery’ and ‘frankly vicious self-confidence’ on display in these works as a group.

In this general chorus of condemnation or dismissal, the Dialogue has admittedly fared somewhat better than the rest. Couched, like Book I of Utopia and the very different Dialogue of Comfort against Tribulation, in More’s favourite and most successful literary form, the Dialogue Concerning Heresies was written with evident zest, and published as the upward curve of More’s career reached its zenith with his appointment as lord chancellor in succession to Cardinal Wolsey.