This was originally a two volume set which is now bound as one. Here is presented an investigation of the nature of the earliest extant records of the supposed communication with angels and spirits of John Dee (1527-1608) with the assistance of his two mediums or 'scryers', Barnabas Saul and Edward Kelly. Volume 2 of this work is a transcription of the records in Dee's hand contained in Sloane MS 3188, which has been transcribed only once before, by Elias Ashmole in 1672. Volume 1 is an introduction and thorough commentary to the text which is primarily explaining its many obscurities. The author describes the physical state of the manuscript and its history then continues with a biography of Dee and his scryers and some background to Renaissance occult philosophy. Further chapters address the arguments that the manuscript represents a conscious fraud or a cryptographical exercise and describe the magical system and instruments evolved during the communications or 'Actions'. The last, fascinating chapter examines Dee's motives for believing so strongly in the truth of the Actions and suggests that a principal motive was the conviction, not held by Dee alone, that a new age was about to dawn upon earth.