What is Yoga: Types of yoga

On a dark night in the 1950s I raced from my bed and huddled at the door to my parents’ room, frightened and still half asleep. I was perhaps five years old, and the vivid imagery of a nightmare was still fresh. It seemed real enough: a snake coiled in my bed—and my parents’ reassurances that it was just a dream were little consolation.
This is one of my earliest dream memories. It was a dream that repeated again and again throughout childhood, adolescence and even occasionally now as I move to middle age. What is a dream? Is there a special significance to a dream about snakes that repeats itself? Might snakes be messengers of the unconscious, or possibly the early sexual stirrings of a child, or then again a communication from another class of beings called nagas (snake kings) by the Tibetans? Perhaps the dream can only be understood within the context of the life of the dreamer, and thus have a specific personal meaning.
Archetypal material, personal anxieties and concerns, foretelling of the future, communication with other dimensions of beings are all possibilities within dream, according to the masters of dreamwork. Nevertheless, this statement should be qualified by saying that few encounter this range of dream experience. For most, dreaming is simply a rehashing of the impressions of the day, within the context of the dreamer’s wishes, fears and personality.
In the 1950s, despite the presence of a few philosophers and contemporary thinkers for whom dreaming held renewed interest, most Americans, myself included, viewed dreams as having little significance. This blithe state of affairs was soon changed by the upheaval of the sixties. From the crucible of collective and personal crises resulting from the dramas of the decade, and concurrent with the popularity of yoga and various meditation forms, the awareness of dreams began to reassert itself in the general culture, and in myself.
My memories of dreams from early childhood to college are little more than a blur. The vivid imagery and sharp recollections of childhood faded into fleeting images or no memory at all. But in 1978, my experience and understanding of the dream condition was radically transformed. I traveled to France to study with a renowned Tibetan lama, Dudjom Rinpoche. Among the topics he taught was dream yoga. Rinpoche spoke clearly about the need to strive for awareness even within the sleeping state. He compared the current sleeping state of mankind with the unconscious sleep of an animal. He lamented the waste of such a precious opportunity for developing oneself. I left the tent where the teachings were conducted in a strange state. All that I saw or heard seemed dreamlike, no doubt due to the great lama’s powerful transmission. This unfamiliar perception lasted the entire day and into the evening, when I prepared to go to sleep.
I resolved to follow Rinpoche’s instructions for developing awareness and prayed for his assistance. That night was unusual also. I fell asleep, but soon became aware that I was sleeping. I lay in a conscious luminous state. It was my first conscious experience of yogic sleep and the natural light of the mind.