पुरुषार्थशून्यानां गुणानां प्रतिप्रसवः कैवल्यं स्वरूपप्रतिष्ठा वा चितिशक्तेरिति।

 
We do not know who Patanjala* was or where he lived.  What we know is that a set of aphorisms has come down to us bearing his name in a short booklet called yogasutram.  The aphorisms are empirical statements on the nature of life in the universe.  They show techniques by which any individual can explore his or her own living identity.  The cosmology of yoga is the most scientific statement of the nature of life in the universe. It calls out for experimentation by anyone who might desire to attempt.  It is believed that Patanjala is a compiler of the material that had been in practice for hundreds of years before his time. We note that the person's name was Patanjala, the technique going by his name is Patanjali.
 
Yoga is not knowledge, it is a subjective realization.  It is a realization that the individual is a part of the cosmic universe to which everything else belongs.  It is non-dual.  We are in yoga when our individual identity is merged with the larger cosmic reality.  Yoga has no memory.  As long as we are examining the universe, there is no yoga.  Patanjala declares that yoga is the restraining of the wanderings of our discriminating nature.  That we can restrain and attain the state of restful bliss in our living identity is the triumph of Patanjala's enunciation.
 
When we have intense concentration in a creative work like writing, music, dance, paint or speech, we do enter the state of yoga.  In the state of yoga, the activity is not personal any more.  One does become a channel on behalf of the cosmos.  Patanjala teaches us if we can prepare ourselves to do all our work in the state of yoga.  
 
This site contains the course syllabus and the class work taught by Bijoy Misra to students at Frog Pond Yoga Center in Princeton, Massachusetts.