In the Western world, "Yoga" is often considered to be either a type of more or less gentle gym, or as a meditative practise. Though the modern practitioner does not usually know very much about its origin, he quickly notes all the positive physical benefits that Yoga brings. Sometimes, a regular practitioner can also begin to feel that there are still greater benefits to reap from Yoga, that it can also bring a certain peace to the mind, and so discover the real depth of this ancient art.

In India, its country of origin, Yoga is seen as a practise that brings endurance, flexibility and balance at a physical level, but it is also often recognized as a more general system of practises aiming to bring also mental balance and spiritual development.

When one speaks of "Yoga", it is important to understand that this is a general term encompassing a wide range of approaches and practises, but that all of these approaches share a common goal: the complete well-being of the person. Different approaches have different names, such as Hatha-Yoga, Raja-Yoga, or Ashtanga-Yoga. The technical approach or aspects of the teachings may vary from one school to another, as each school is structured around the teaching or lineage of a specific Sage or "Master". A few of the best-known contemporary schools are for instance: the "Iyengar" school of B.K.S. Iyengar, the "Viniyoga" school founded by T. Krishnamacharya and currently directed by his son T.K.V. Desikachar, the "Ashtanga" school of K. Pattabhi Jois, or the "Rishikesh School" of Swami Sivananda Saraswati. All of these schools, though differing in their approaches and techniques, share the aim of helping the student progress in his quest for his well-being. To put it differently still, they all strive to help the Yoga practitioner to grow and blossom in all the aspects of his Being and of his existence in view of attaining his ultimate human potential.

Sanskritists tell us that the word "Yoga" comes from the Sanskrit root YUJ, meaning to join or unify. This Sanskrit form is found in the Latin verb " jungere ", meaning to bind. It can still be found in the English verb "to join" and noun "yoke", as well as the French verb " joindre " (to join, to bind) and noun " joug " (yoke or harness).

The form, the techniques and the goals of Yoga are formalized in a famous treatise called the "Yoga-Sûtra" of Patanjali (or Pâtañjali). In the Western world, the external or physical aspects of these teachings are often referred to as "Yoga" or "Hatha-Yoga".

Legend has it that Patanjali, half-man and half-snake, was an avatar of an Indian divinity (Vishnu, Ananta, or Adisesa) and that it was he who brought three essential teachings to India: Sanskrit (the grammar) for instruction, Ayurveda to heal the ailments of the body, and Yoga to appease the mind and ensure spiritual growth.

Historically, the text of the "Yoga-Sutra" is attributed to a sage named Patanjali, who is thought to have lived at some time between the 2nd century BC and the 5th century AD. It is generally accepted that the contents of the "Yoga-Sutra" do not constitute a new and original contribution from Patanjali himself; rather, his text is seen as an extraordinarily concise though complete compilation and formalization of much older traditional teachings that go back to about 5000 BC or further.

Patanjali's "Yoga-Sutra" are composed of 196 aphorisms that define Yoga by establishing its end as well as its fundamental techniques. Right from the start of the treatise, Patanjali states that Yoga is a path based on techniques such as Asana, whose ultimate aim is to attain "Grace" or "Liberation". Patanjali describes this path and gives it eight aspects. These eight aspects taken together constitute what is called "Ashtânga-Yoga" (eight-limb Yoga) or "Râja-Yoga" (Royal Yoga).

The eight aspects are the following:

1. Yama: the restraints (five negative injunctions)
2. Niyama: the observances (five positive injunctions)
3. Asana: the execution of postures
4. Pranayama: the discipline of breath
5. Pratyahara: the withdrawal of the senses
6. Dharana: the focus of attention
7. Dhyana: meditation
8. Samadhi: "Grace" or "Liberation"

Patanjali's "Yoga-Sûtra" is extremely concise and, by itself, would be incomprehensible to most students of Yoga. It has thus been the object of many learned presentations and commentaries, amongst which the classical reference is the text called "Yoga-Bhâshya", attributed to the sage Vyâsa, who lived between the 6th and 7th century AD. Note that two renowned and contemporary yoga masters, B.K.S. Iyengar and T.K.V. Desikachar, have both written and published their own commentaries on Patanjali's text.

Hatha-Yoga, as it has been popularized in the Western world, is generally thought of as the practise of two of these eight aspects: âsana and prânâyâma.

The Hatha-Yoga postures are described in much greater detail in a classical Sanskrit treatise called "Hatha-Yoga Pradîpîka", written by Swami Svatmarama, who lived around the 15th century AD. However, the practise of postures or asana is much more ancient, going back with certainty to the "Indus Valley" civilization, around 5000 years BC.

After having mentioned the nature and origins of what is commonly called " Yoga " in the Western world, let us add another consideration on Yoga. The "Yoga" that is described by Patanjali is in reality a complete path or roadmap that aims to help a person in attaining his ultimate potential: "Grace" or "Liberation". In this context, "Yoga" should technically be called "Râja-Yoga" or "Ashtânga-Yoga". But this type of Yoga, whose aim is nothing less that spiritual growth, is but one particular path amongst other spiritual paths.

Indian tradition recognizes four major paths or types of classical spiritual progression:

1. Karma-Yoga : the Yoga of Action ;
2. Bhakti-Yoga : the Yoga of Devotion ;
3. Râja-Yoga : the Yoga of Patanjali ;
4. Jnaña-Yoga : the Yoga of knowledge.