Following the hapless Hampton Court Conference, little groups of English Christians (Separatists) began to break away from the established church. As early as 1606, one group, led by John Smyth, migrated to Holland. Prominent among them was Thomas Helwys. In 1611/1612, Helwys and others returned home where they founded at Spitalfield the first General Baptist congregation in England. Helwys had with him a manuscript entitled A Short Declaration of the Mystery of Iniquity in which he proposed the notion of liberty of conscience, freedom of religion. This may have been the first such declaration in English. Helwys published the manuscript in 1612. That publication probably cost him his freedom, perhaps even his life. By the beginning of the twentieth century, only four known copies of the book survived. Now, thanks to the careful work of Richard Groves, Helwys's The Mystery of Iniquity is available in a reader-friendly edition. Groves's introduction sets the document in context, not only as an important and influential historical event but as shedding yet more light on whence we have come. Students, historians, Christians, Protestants, Baptists - all for whom freedom of conscience is important will welcome this reissue in modern dress of a religious liberty classic.