Historically, Yoga has not grown up with views and practices varying between school or teacher. However, all paths share the same moral requirements (Yama and Niyama) as a foundation, and have the same end aim of ecstatic experience through transcending one's limited consciousness to obtain Self- or God-Realisation. B.K.S. Iyengar captures this commonality nicely when he states in his book "The Tree of Yoga":

"In yoga... many may take one path as a key in order to experience self-realisation while others may take another path, but I say there is absolutely no difference between the various practices of yoga."

Historically speaking, the most significant of all schools of Yoga is the classical system of Patanjali. This system, captured in his Yoga Sutras, is often equated with Raja Yoga and is a summary of generations of yogic experimentation and culture.

Within the realms of Hinduism, six major forms of Yoga have gained prominence: Raja Yoga, Hatha Yoga, Jnana Yoga, Bhakti Yoga, Karma Yoga and Mantra Yoga.

Raja Yoga (often referred to as Ashtanga Yoga) and Jnana Yoga approach Self-realization through transcendence and transformation of the mind.

Hatha Yoga focuses on the physical but with similar goals to Raja Yoga.

The main difference between Raja and Hatha is that Raja Yoga uses asanas to mainly get the body ready for prolonged meditation, and hence focuses more on the meditative asana poses: Lotus Pose (Padmasana), Accomplished Pose (Siddhasana), Easy Pose (Sahajasana) and Pelvic Pose (Vajrasana); Hatha Yoga utilizes most of the asana poses. Similarly, Raja Yoga's use of Pranayama is also devoid of extensive locks (Bandha).