First, Sikhism is not the basis for shabd yoga. Rather, Sikhism (as founded by Nanak) grew out of the Sant Tradition which was prevalent in North India for many centuries. Such Sants as Kabir and Namdev predate Guru Nanak and they each taught variations of sant mat and shabd yoga.

     The best scholar in this are is W.H. McLeod who has written a number of fine academic studies which clearly shows that Sikhism, like the Kabir-panthis, like the Sat Namis, and like the Radhasoamis later, were manifestations of the Sant movement which had spread throughout India as a philosophical school which focused on a number of illuminating tenets, not the least of which is the listening to inner sound.

     In this regard, I suggest: Guru Nanak and the Sikh Religion (Oxford) The Evolution of the Sikh Community (Oxford) and the edited volume: The Sants (published by the University of California in conjunction with Motilal in Delhi).

     Also refer to Vaudeville's Kabir (Oxford) and Juergensmeyer's Radhasoami Reality (Princeton) and Sikh Studies (G.T.U.)

     Shabd yoga is most likely traceable--at least in its Indianized forms--to the Vedic period, if not before.

     Thus there are a number of different schools of shabd yoga; many of which, including Sikhism, focus meditation on the eye center and do not at all advocate kundalini yoga. Indeed, in the Guru Granth Sahib Nanak argues against such yogic systems which concentrate on the lower body and breathing.

     Paul Twitchell learned of shabd yoga from Kirpal Singh, who was himself initiated by Sawan Singh, who was in the lineage of Jaimal Singh and Shiv Dayal Singh--the founder of Radhasoami.

     Radhasoami, however, is not an offshoot of Sikhism; it is rather a modern manifestation of Sant Mat, which predates both Sikhism and the Kabir-panthis. Thus today there are numerous schools of Radhasoami, some which have nothing to do with Sikhism.

     The reason most people mistakenly believe that Radhasoami is connected to Sikhism is because of the popularity of the Beas and Ruhani Satsangs which have had exclusively Sikh-born masters. However, Tulsi Sahib--Shiv Dayal Singh's guru (the founder of Radhasoami) was not a Sikh, nor are the majority of Radhasoami or shabd yoga masters in India.

     Twitchell learned what he knew of the tradition primarily from his study under Kirpal Singh. It was only later (when the former President of Eckankar, Louis Bluth, offered his R.S. library to Twitchell) that Paul learned more about the history of shabd yoga, but even then he got most of his facts and details wrong. I say wrong not in a theological sense, but in terms of simple history: wrong names, wrong dates, wrong facts, etc.

     Eckankar was indeed mostly based upon shabd yoga in the beginning because that is exactly what Twitchell himself told Kirpal Singh (in a correspondence--which I saw) he was doing.

     Again, the problem that G, David Rife, myself, and others have with Twitchell is that he was not honest about his spiritual roots. This dishonesty was extensive: from plagiarism to coverup.

     Since shabd yoga concentrates on the individual and his or her access to mystical experiences, I am not at all surprised that "Eckankar" works for people like Holly and others. Indeed, all religions and all systems "work" in that sense. I mean astrology also is very meaningful to millions, even though it is based upon a pre-scientific understanding of cosmology, quantum theory, and relativity.

     So the key here is to realize that what is "working" in Eckankar has much more to do with the structural, even inherent, possibilities of every individual to have transpersonal experiences beyond the rational mind than it does with any "organization."

     But let us not condone any one organization which has an almost built-in tendency to lie about its past and to deceive its future members by not cleanly and clearly explaining how it began.

     No doubt, every group--from Radhasoami to Sikhism to Christianity--should also be scrutnized thoroughly.

     There is nothing negative about this, I believe. Rather, it makes us better understand what is what.

Heart to Heart Talks, Volume One and Two by Kirpal Singh (which mentions Paul Twitchell)

Thus Saith the Master by Charan Singh (which mentions Twitchell's plagiarism)

The Encyclopedic Handbook of Cults by J. Gordon Melton (which outlines, in brief, Eckankar's history)

and the forthcoming:

LIFE 102: what to do when your guru sues you by Peter McWilliams.

     It talks about how J.R. was connected to Eckankar and how he deceived thousands, etc.