The last four are internal, and they automatically follow when the first four are mastered. Pratyahara means that anywhere you look, you see God. Then for you the world is colored by God. Whatever you see, you identify it with your Atman. The scriptures say that a true yogi's mind is so absorbed in the lotus feet of the Lord that nothing distracts him, no matter what happens in the external world.
Yoga is possible for anybody who really wants it.
Yoga is universal. Yoga is not mine. But don't approach yoga with a business mind-looking for worldly gain. If you want to be near God, turn your mind toward God, and practice yoga. Sandra Anderson is a contributing editor to Yoga International.