5Cotton Mather chronicles the Salem witch trials which took place in New England in the late 18th century. Together with the trials, this book holds detailed accounts of devilish phenomena Mather believed were linked to the discovery of the local witches.

Mather discusses a range of spiritual phenomena reported by various figures in the fledgling society of New England. Sudden apparitions, visions, and other strange goings on which she believed were linked to the frequent finding of witches are cataloged. The bulk of the text however is concerned with the trials of many witches, the causes of their accusations, and the circumstances under which they were tried.

Several of the witches are named, with the dates of their trials also recorded. Mather's book is today one of the best and most complete primary narratives of what came to be known as the Salem witch trials; with accounts of witnesses, judges, and evidence put forward all present. Furthermore, Mather's book was published in 1693, shortly after the trials were concluded.

Alongside the social commentary, Mather asserts her belief that the various witches and associated oddities were part of the 'Invisible World'. This realm, so Mather believed, is unapparent to ordinary human eyes, and only makes itself known with a variety of unusual and wondrous phenomena connected with the accused witches.