The main exposition of the system of Sa@mkhya and Yoga in this section has been based on the _Sa@mkhya karika_, the _Sa@mkhya sutras_, and the _Yoga sutras_ of Patanjali with their commentaries and sub-commentaries. The _Sa@mkhya karika_ (about 200 A.D.) was written by Is'varak@r@s@na. The account of Sa@mkhya given by Caraka (78 A.D.) represents probably an earlier school and this has been treated separately. Vacaspati Mis'ra (ninth century A.D.) wrote a commentary on it known as _Tattvakaumudi_. But before him Gaudapada and Raja wrote commentaries on the _Sa@mkhya karika_ [Footnote ref 322]. Narayanatirtha wrote his _Candrika_ on Gaudapada's commentary. The _Sa@mkhya sutras_ which have been commented on by Vijnana Bhik@su (called _Pravacanabha@sya_) of the sixteenth century seems to be a work of some unknown author after the ninth century. Aniruddha of the latter half of the fifteenth century was the first man to write a commentary on the _Sa@mkhya sutras_. Vijnana Bhiksu wrote also another elementary work on Sa@mkhya known as _Sa@mkhyasara_. Another short work of late origin is _Tattvasamasa_ (probably fourteenth century). Two other works on Sam@khya, viz Simananda's _Samkhyatattvavivecana_ and Bhavaga@nes'a's _Sa@mkhyatattvayatharthyadipana_ (both later than Vijnanabhik@su) of real philosophical value have also been freely consulted. Patanjali's _Yoga sutra_ (not earlier than 147 B.C.) was commented on by Vaysa (400 A.D.) and Vyasa's bhasya commented on by Vacaspati Mis'ra is called _Tattvavais'aradi_, by Vijnana Bhik@su _Yogavarttika_, by Bhoja in the tenth century _Bhojav@rtti_, and by Nages'a (seventeenth century) _Chayavyakhya_.
Amongst the modern works to which I owe an obligation I may mention the two treatises _Mechanical, physical and chemical theories of the Ancient Hindus and the Positive Sciences of the Ancient Hindus_ by Dr B.N. Seal and my two works on Yoga _Study of Patanjali_ published by the Calcutta University, and _Yoga Philosophy in relation to other Indian Systems of Thought_ which is shortly to be published, and my _Natural Philosophy of the Ancient Hindus_, awaiting publication with the Calcutta University.
Gu@naratna mentions two other authoritative Sa@mkhya works, viz. _Ma@tharabha@sya_ and _Atreyatantra_. Of these the second is probably the same as Caraka's treatment of Sa@mkhya, for we know that the sage Atri is the speaker in Caraka's work and for that it was called Atreyasa@mhita or Atreyatantra. Nothing is known of the Matharabhasya [Footnote ref 323].