Giambattista della (John Baptist) Porta (1535-1615), was a Neapolitan scholar of notable ability who had devoted great attention to the study of natural and physical science. Porta visited most of his known world to gather and perfect the knowledge utilized in his writings. His first work, "Magia Naturalis"- "Natural Magick" was first published in 1558 in "four" books (written, according to the author, "Porta, " when he was fifteen years old, - see "Preface To The Reader" in "Natural Magick"). It was later expanded to twenty books compended into one volume in 1584. In this form the book had a great vogue, being translated from the original Latin into the principal European languages, and republished in the Latin edition in many places for a hundred years. The version presented here is the final compendium of his life's work, completed when he was fifty years old, transcribed from a original 1658 English translation. The value this book gives the reader of the actual perspective of those early scientists and the way they perceived their known universe was as precious then as it is now. It should be remembered that few in Porta's time were free from credulity toward many marvels and superstitions which were inherited from the past and Porta's work shows that he was no exception, as much of the "marvelous" is found in his writings. On the whole, however, his information is definite and practical and his work is a good as could be expected of one not himself a practical experimenter or investigator, but a conscientious and scholarly student of literature, ancient and contemporary. This point is critical as it frees him of the certain prejudice a trained scientist may have given to different schools of thought. Therefore the reader is presented with a clear, unbiased view of the concepts, perception and achievements of a host of historically important scientists and philosophers through Porta's writings.