Gangraena is a book by English puritan clergyman Thomas Edwards, published in 1646. A notorious work of heresiography, it appeared the year after Ephraim Pagitt's Heresiography. These two books attempted to catalogue the fissiparous Protestant congregations of the time, in England particularly, into recognised sects or beliefs. Pagitt worked with 40 to 50 categories, Edwards went further with around three times as many, compiling a list of the practices of the Independents and more extreme radicals: Thomas Edwards, in his Gangraena (1645), enumerated, with uncritical exaggeration, no less than sixteen sects and one hundred and seventy-six miscellaneous "errors, heresies and blasphemies," exclusive of popery and deism. Source: Wikipedia (en)