In all times people have believed that human exists after death and that there is an invisible world. There have also been people who have sought and found answers about the purpose of existence, life after death and the spiritual realm. Finnish writer Pekka Ervast describes the requirements for spiritual knowledge on the basis of Indian Vedanta philosophy and Christian occultism. In the first stage knowledge from the visible and invisible world is gained through the senses. In the second stage the truth seeker becomes self-aware in the invisible world. And finally in the third stage human becomes one with God - the spirit of Brahman, and gains the highest knowledge attainable. The first chapters examine the purpose and structure of both the presently existing as well as the yet dormant senses of a human being. The following chapters examine the yoga practices of Patanjali and their influence on human constitution. And finally Ervast examines the life after death and the experiences which one faces on the spiritual path. Pekka Ervast (1875-1934, Founder and General Secretary of the Finnish section of The Theosophical Society, 33° founder-member of the Finnish section of the International Order of Freemasonry Le Droit Humain, Founder-President and Grand Master of the Finnish Rosicrucian Freemasonry.