Everyone who has started out along this path has achieved some improvement in their life circumstances. Even the most rudimentary yoga practices when learned correctly may generate feelings of bliss and a heightened perception.

Yoga Sutras
For our purposes the most important teachings on yoga are contained in the Yoga Sutras of Patanjali - a collection of 195 philosophical aphorisms from around the second century. The Yoga Sutra is divided into four chapters:

Samadhi Pada (chapter on samadhi or transcendental trance)
Sadana Pada (chapter on practice)
Vibhuti Pada (chapter on powers obtained from yoga practice)
Kaivalya Pada (chapter on liberation)

Samadhi Pada
In his text, Patanjali describes three distinct approaches to the attainment of Yoga. The first is for adepts who have already travelled far on the path of yoga and here he gives his seminal definition of Yoga:

1.2. Yogas-chitta-vritti-nirodhah
- yoga is the controlling or restraining of mental fluctuations.

1.3. Tada drastuh sva-rupe'vasathanam
- then the "seer" (witness) experiences himself in his own true form,

1.4. Vritti-sarupyam-itaratra
- otherwise the seer identifies with the changing nature of the mental fluctuations.

Normally we are totally immersed and involved in the ever fluctuating phenomena we experience as sense impressions, thoughts, feelings and memories. This nexus of "expereience" somehow congeals into what we think of as an ego, self or identity.

However, according to Patanjali, this ever-changing entity we normally think of as the self, is nothing but the product of purely material processes. According to him, the nature of the Self is unchanging - it does not think or act or desire - it is simply a witness.

The intellect, ego, mind and senses have no inherent consciousness, they are purely functional and material (all be it subtle) in nature - they do not constitute our true identity, they are only there to serve that identity.

When the mental fluctuations are restrained, the Self experiences itself in its own true form. This may happen to us in fleeting moments, but in order to sustain a continuous awareness of the Self, intense discipline and practice is required.

Patanjali gives no explanation as to why the Self has fallen into delusion. He just observes that this is so, and that this is the cause of all suffering and sickness. The rest of his treatise gives methods for attenuating this delusion and describes the various stages the aspirant may experience on his way towards liberation from ignorance.

The Samadhi Pada (first chapter) takes a philosophical approach to obstacles which stand in the path of the aspirant, assuming that he has already attained some significant level of moral development on the path of yoga.

Sadana Pada
The reason for confusion and delusion is the advent of desire and aversion. Attachments, greed, egoism, hatred, violence, jealousy etc, to whichever degree they are experienced in the mind, prevent us from seeing what is true - what we see is distorted.

When we are influenced by these poisons, as they are called in the yogic literature, and we wish to come to clarity about our true nature, we are in need of powerful tools to help reduce them. For this, intense practices are required.

The Sadana Pada (second chapter) is the section on practice: for the aspirant with some degree of development on the path of yoga, Patanjali suggests Kriya Yoga - intense practice, self-study and surrender to the ideal of yoga are sufficient for students at this level.

For all others there is the path of Ashtanga Yoga, "Ashto" meaning eight and "anga" meaning limb or part - eight part or eight step yoga.