Right from the times of Sikh Gurus many groups emerged in the garb of Sikhism with parallel Guruships but ended as rejected Out-Groups: Adversaries of Sikhism. Notable among them are Minas, Dhirmalias, Ram Raiyas, Ajit Malias, Niranjanias, Nirankaris, Radha Suamis, Namdharis. In 1960s Yogi Bhajan floated his brand of Tantric Yoga Sikhism in U.S.A.; a crude mixture of Sikhism and Tantric Yoga, which is reproved in the Sikh Scriptures. But still this new brand of Sikhism received sanction from S.G.P.C. through its President, Gurcharan Singh Tohra, Secetary Giani Mahinder Singh, Hukam Singh etc. Late Dr Trilochan Singh during his tour of U.S.A. (1977) exposed this anti-Sikh movement in the first edition the book Sikhism and Tantric Yoga, and the book proved a turning point in the lives of many American converts. The author predicted that this book will be relevant even after 50 years of its publication and the Tantric brand of Yogi Bhajan will collapse due to its inherent contradictions. After the demise of Dr Trilochan Singh, (February 15, 1993) the book was revised, documented and enlarged by his son Professor Anurag Singh. This extensively researched and profusely documented edition is now being given as a gift to those who value Sikhism in its pristine purity.