While I don't deny the fact that yoga is a vital part of Hinduism, and may be considered part of "worship" for many Hindus, in American culture, yoga has become so mainstream and divorced from any religion that most of Hunt's arguments are fallacious.
Hunt also uses outdated references for the majority of the book (pre 1990s references popped up frequently, and I don't think I saw anything dated earlier than the mid 2000's), which makes it seem like he did no research into modern yoga and the culture of physical well-being that surrounds it in America. In fact, he states outright that there is no difference between religious yoga and the watered-down version currently most commonly practiced in the US today.
Finally, Hunt makes the preposterous claim that Christians practicing yoga can become possessed by demons. He posits the theory that because in its original religious context, yoga is seen as an opening of the body and the mind/spirit, it's practitioners become open to demonic possession. He equates this to the (VERY different) practice of VooDoo priests and priestesses of deliberatly calling spirits (loa) down to "ride" them. To his mind, there is no difference between them, because any form of "openness" whether that's meditation, yoga, hypnosis, etc., allows for evil spirits/demons to take possession of your mind and body. He also makes no distinction between Christians and non-Christians, saying that yoga will allow even Christians to become demon possessed (Paul states that the indwelling spirit of Christ protects us from possession, but not influence, by demons).
Overall, I cannot recommend this book, as it contradicts biblical truth.