Philosopher and long-time Buddhist practitioner, Ken Wilber, shares with us a 10,000 foot view of the terrain of meditative experience. He describes several of the most common Buddhist maps and their progression, including the one presented in the Visuddhimagga (one of the most prevalent in the Theravada tradition), the 10 ox herding pictures in the Zen tradition, and the Anuttara Tantra from the Tibetan tradition.
He also gives an overview of the very difficult stages of practice called the Dark Nights. These are periods where after being plunged into a whole new experience of reality we have it stripped from us and feel like we have lost what was once discovered. Another meaning of the dark night has to do with dis-identifying with previous levels of consciousness, and the difficult journey of releasing our grasping and addiction to these lower levels.