Every ancient book on yoga (not the modern nonsense) tells us that yoga has to be practised naked. But the American businesses who make millions of $ in "yoga clothes" prefer that people should never read the text like Hatha Yoga Pradipika.

Dhyan is "prayer" -- dhyan yoga is acheiving things through prayer and meditation.

where as Hatha Yoga is -- is Sun & Moon yoga.....

William Zorn has written:

'True yoga' -- subject(s): Hatha yoga

'The easy yoga exercise book' -- subject(s): Hatha yoga, Yoga

Iyengar, in order to enable more people to practise basic Hatha Yoga, invented "Iyengar Yoga" that is mostly practised outside India. Classical Hatha Yoga is more complex and encompasses a lot more.

Michele Picozzi has written:

'Controlling Herpes Naturally'

'Pocket guide to hatha yoga' -- subject(s): Hatha yoga

'Yoga'