According to the book’s preface, Josiah Brigham states that, from August of 1854 until March of 1857, the medium Joseph D. Stiles, while entranced, allowed the spirit of John Quincy Adams to communicate through him using automatic writing. These sessions were held in Brigham’s home in Quincy, Mass. and at his son-in-law’s home in Boston, and it was Adams himself who requested that the messages be published. Brigham further states:
Mr. Stiles is a respectable, unassuming young man, of only common-school education, with no pretensions to more than common capabilities. He is a printer by trade, and worked at that business until he perceived he possessed mediumistic powers. His organization is such that he is very susceptible to spirit-influence, and is one of the best writing-mediums in the country.
John Quincy Adams’ alleged discourse from beyond the veil is very Dante-esque. Speaking from “Spirit Land, Sixth Sphere,” he vividly illustrates for the reader what he sees or has seen in the different spheres of the afterlife. He also describes his meetings with relatives, as well as Biblical and historical figures in the spheres--delivering their many messages of philosophy and morality to the corporeal reader. Adams also speaks of his visits to earth, during which he would visit living relatives and attempt to prove to mortals the existence of the afterlife.
This book is available online in its entirety and can be viewed by visiting: https://archive.org/details/twelvemessagesfr00stil