The asana is an enquiry: "Who am I?" Throwing out the parts until only the Self is left.  The final pose is "I am."
- BKS Iyengar

(from the Official BKS Iyengar Yoga Website -  http://bksiyengar.com/modules/IYoga/iyoga.htm)

Sage Patanjali, who has penned this subject in his treatise Yoga Darshana defines yoga as chitta vritti nirodha. Chitta is the consciousness which includes the mind, the intellect and the ego. Yoga is a method of silencing the vibrations of the chitta. 

The eight aspects (astanga) of yoga are :

• Yama and Niyama
• Asanas
• Pranayama
• Pratyahara
• Dharana
• Dhyana
• Samadhi
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Yogacharya B.K.S. Iyengar with his intellectual and spiritual practices has masterminded the techniques which can be used by all practitioners of yoga. "Research based experience" and "experience based research" has helped him in evolving this technique which is now known as"Iyengar Yoga". He has therefore made it possible for ordinary human beings to experience the wisdom of the yoga sutras.

Iyengar yoga is meant for all and is a way of life. The use of props, designed by Guruji , such as wooden gadgets, belts, ropes helps the practitioner to achieve perfection in any asana. Regular practice of 'Iyengar Yoga' definitely integrates the body, mind and emotions.

तदर्थ एव दृश्यस्यात्मा॥२१॥