"Liber 777 Vel Prolegoma Symbolica Ad Systemam Sceptico-Mysticae Viae Explicande, Fundamentum Hieroglyphicum Sanctissimorum Scientiae Summae" is designated a "Class B" document by Crowley. The title refers to a lightning flash descending the diagrammatic worlds, the zig-zag pattern suggesting three diminishing 7s. It consists of roughly 191 columns, with each row corresponding to a specific Sephirah or path on the Tree of Life for a total of 35 rows and is used for a quick reference for corresponding mnemonics and factors of religion for use in magic (for instance, an evocation of Venus would have one looking across that column for the colour corresponding to Venus that will be the colour of his or her robe, and then Venusian incense, etc.).