Actually, most of the material comes from Agrippa's Libri tres de occulta philosophia, the Third Book of Occult Philosophy attributed to Agrippa, and Pietro d'Abano's Heptameron. 
The book was originally published with three books, in one volume, as was the case with so many texts of this period. It is a popular misconception that there were two, separate volumes. The "third volume" is merely short biographies of noted occultists. Today it is reprinted in a single volume. It facilitated the modern revival of magic by making information from otherwise rare books readily available. It may have influenced novelist Edward Bulwer-Lytton and occultist Eliphas Levi. More controversially, it has been identified as an influence on Joseph Smith, Jr., founder of the Latter Day Saint movement, in Reed C. Durham, Jr.'s speech "Is There No Help for the Widow's Son?"