https://en.wikipedia.org/wiki/Franz_Bardon
Wikipedia said:Bardon's works are most notable for their simplicity, their relatively small theoretical sections, and heavy emphasis on practice with many exercises. Students of his, such as Emil Stejnar, Walter Ogris, Martin Faulks, William Mistele and Rawn Clark consider him to have written the best training programs of any magician of the 20th century. They were written with the intention of allowing students who wished to practice magic the means to do so if they could not study under a teacher.