Yoga
The word Yoga is derived from the Sanskrit root Yuj, which means to unite, to join, to add.

The union in Yoga, if considered at the gross physical level, is between the upper brain and the lower brain, the conscious with the subconscious. At a subtle level the union of yoga is between one's individual consciousness and cosmic consciousness.

Yoga presents a system that creates a state of unification of mental processes and consciousness. Yoga is based on particular disciplines and exercises through which union of individual and cosmic consciousness may be obtained by anyone who chooses to adhere to the prescribed system. Yoga not only describes all mental states, aspects and dimensions possible within the individual, but also advocates practical games to be played with the mind to control its functioning and to achieve peace. Meditation is only one aspect of Yoga.

Essentially the yogi will choose according to his temperament to follow one of the 3 yoga paths. All three in combination or not, may lead the yogi to obtaining the union between individual and cosmic consciousness:

There are many yoga traditions and practices, which in essence all have the same goal : the union with the divine.

The overall tradition :

Tantra Yoga (Maha Y)
Ashtanga Yoga

The four main traditions :

Mantra Yoga
Hatha Yoga
Laya Yoga (Kundalini Y.)
Raja Yoga

Other traditions

Yoga and Indian psychology

All these traditions are based on the unique Indian Psychology. Also read the abstracts on "Mind, Ego and Intellect" and on "The five Koshas" by Wil Geraets.

The above overview was extracted and synthesized from various sources, among which the following are the most important :

• the "Chakras" book, which offers detailed information on all main techniques and on chakra meditation, which involves all aspects of Ashtanga.
  
• The "Tools for Tantra" book, which offers highly detailed information on Mantra and Yantra Yoga.
  
• The "Breath, Mind and Consciousness" book, which is the main book on Swara Yoga