Satan's Invisible World Discovered $b or a choice collection of modern relations, proving evidently, against the atheists of this present age, that there are devils, spirits, witches, and apparitions, from authentic records, and attestations of witnesses of undoubted veracity. To which is now added, that marvellous history of Major Weir and his sister, the witches of Bargarran, Pittenweem, Calder, &c.

"Satan's Invisible World Discovered" by George Sinclair is a collection of accounts and testimonies relating to beliefs in witchcraft, spirits, and apparitions, written in the early 19th century. The work presents a compilation of narratives intended to counter atheism by illustrating the existence and influence of supernatural forces in the world, as recounted by various witnesses. The opening of this work introduces the reader to notable narratives, including the troubles faced by Sir George Maxwell due to witchcraft, focusing on a wax effigy created to harm him. It recounts the involvement of a dumb girl who reveals supernatural insights and various accusers of witchcraft, culminating in a dramatic trial and confessions that highlight the widespread fears and societal implications tied to witchcraft in the era. The initial accounts set the tone for the exploration of the deeper themes of faith, skepticism, and the thrall of superstition in a seemingly rational age. (This is an automatically generated summary.)

George Sinclair (Sinclar) (ca.1630–1696) was a Scottish mathematician, engineer and demonologist. The first Professor of Mathematics at the University of Glasgow, he is known for Satan's Invisible World Discovered,, a work on witchcraft, ghosts and other supernatural phenomena. He wrote in all three areas of his interests, including an account of the "Glenluce Devil", a poltergeist case from c. 1654, in a 1672 book mainly on hydrostatics but also a pioneering study of geological structures through his experience in coal mines.