The Wonders of the Invisible World was a book written by Cotton Mather and published in 1693. It was subtitled, Observations As well Historical as Theological, upon the Nature, the Number, and the Operations of the Devils. The book defended Mather's role in the witchhunt conducted in Salem, Massachusetts. It espoused the belief that witchcraft was an evil magical power. Mather saw witches as tools of the devil in Satan's battle to "overturn this poor plantation, the Puritan colony", and prosecution of witches as a way to secure God's blessings for the colony. Its arguments are largely derivative of Saducismus Triumphatus by Joseph Glanvill. A copy of Glanvill's book was in Mather's library when he died. Robert Calef published a refutation of Mather's book in 1700. Source: Wikipedia (en)