Narby’s central message is that shamanic knowledge, gained from direct communication with certain hallucinogenic plants, predates by centuries if not millennia modern scientific data about the basis of life. He notes that shamanic visions of entwined or double serpents, recorded throughout history and across the world, foreshadowed in remarkable detail the twentieth-century discovery of the double-helix or “twisted ladder” structure of DNA, the fundamental molecule of life.

Many shamans use special plant “guides,” such as ayahuasca, peyote, or psilocybin mushrooms, along with special chants, whistles, drumming, or dancing to prepare the mind for receiving altered states of consciousness capable of penetrating alternative realities. In Narby’s case, his “spirit-guide” was ayahuasca, and he writes of his first initiation:

"These enormous snakes are there, my eyes are closed and I see a spectacular world of brilliant lights, and in the middle of these hazy thoughts, the snakes start talking to me without words. They explain that I am just a human being. I feel my mind crack, and in the fissures, I see the bottomless arrogance of my presuppositions. It is profoundly true that I am just a human being, and, most of the time, I have the impression of understanding everything, whereas here I find myself in a more powerful reality that I do not understand at all and that, in my arrogance, I did not even suspect existed. I feel like crying in view of the enormity of these revelations. Then it dawns on me that this self-pity is a part of my arrogance. I feel so ashamed that I no longer dare feel ashamed."