Maharshi Patanjali has explained yoga properly in his book "Yogasutra." He has mentioned eight aspect of yoga through which human being can attain overall development of his personality. They are known as steps of yoga.
Samadhi Dhyana Rajyoga Dharana Pratyahar Pranayama Huthyog Asana Niyam Yam (i) Yam : The meaning of yam is not to indulge in negative behaviour. Yam includes Ahimsa or non violence, Satya - truthfulness, Asteya-not stealing, Brahmachaiya - celibacy, and Aparigraha - not to possess. Ahimsa means not to cause any damage to other living beings by deeds, thought and language. Satya means not to tell lie. Asteya means not stealing things belonging to others. Brahmacharya means not to have sexual life. While Aparigraha means not to possess or accumulate things beyond one's actual needs.
(ii) Niyam : Niyam means to observe positive aspects in behaviour. Shaucha, Santosh, Tapa, Swadhyaya and Ishwara Pranidhana are included in Niyam. Shauch means purity of internal and external body. Santosh means contentment with whatever one has. Tapa means to train the body so that it can do particular task efficiently. Swadhyaya means to cultivate habits of studying spiritual scripts regularly. Ishwar Pranidhan means to surrender ourself to the almighty.
(iii) Asana : The special designs of posture that stabilise mind and body are called Asanas. They help (vi) Dharana : Steadiness of mind is called Dharana. In this stage, the person keeps his mind empty of thoughts for a long period and still concentrate continuously on one point or thing.
(vii) Dhyana : It means to concentrate on one object or stimulus. Due to deep concentration, a feeling of unity of mind and the object of concentration develops.
(viii) Samadhi : It is a state where both the subject and the object become inseparable. There are no problems and the person feels complete unity with the almighty.
At present several miniature techniques thắt include one, two or many steps of the yoga have been developed for the treatment of mental, physical and psychological disorders.