That changed with the arrival of Bernhard's diverse circle. Gentiles flocked to an introductory course she arranged in Manhattan.
It was difficult for some former disciples to square the ecumenical approach with the Kabbalah Centre they had known.
Jeremy Langford, an early follower who left the center in 1984 over concerns about its authenticity, said reports about gentile celebrities attending classes confirmed his belief that the Bergs were teaching "pop, light, quasi New Age, ersatz kabbalah."
Nothing garnered bigger headlines for the center than the arrival of Madonna. She enrolled at the L.A. center in 1996 at Bernhard's suggestion.
"It didn't really matter that I was, you know, raised Catholic or I wasn't Jewish and I felt very comfortable and I liked being anonymous in a classroom environment," she told television personality Larry King in 1999.
To the surprise of her detractors, Madonna stuck with her studies. She attended Sabbath services, had one-on-one study sessions with Yardeni, enrolled her daughter in the center's Sunday school and chose a Hebrew name, Esther.
The Kabbalah Centre suddenly had cachet among the rich and famous, and through them entree to a wider audience. Yardeni was at ease with big names and egos, and the Bergs tapped him as their Hollywood emissary. He had once worked as a door-to-door chevre and had a humility and directness that the powerful and well-connected found refreshing.
"I thought Eitan was very, very bright and a very good spiritual teacher," said talent manager and producer Sandy Gallin, who first heard Yardeni speak at Barr's home. He said one-on-one tutoring with Yardeni taught him "to take the high road and to understand there is a greater power than you."
The list of celebrities attracted to the center grew to include Elizabeth Taylor, Gwyneth Paltrow, Britney Spears and Paris Hilton.
Yardeni held exclusive sessions at Westside mansions. Producer Christine Peters hosted one that drew entertainment figures that included her then-boyfriend, Viacom Executive Chairman Sumner Redstone.
"He was so wonderful," said Cindra Ladd, wife of former 20th Century Fox President Alan Ladd Jr., recalling classes she attended at a Pacific Palisades home. She said Yardeni would begin by reading from the Zohar and the Torah, the first five books of the Bible, in Hebrew and English. He would relate stories about Moses and other biblical figures to daily life. Topics included how to achieve lasting fulfillment, how to transform oneself "in the light of God" and how to refrain from gossip.
"That was the hardest one for everyone," Ladd joked.
Yardeni's teachings about finding meaning beyond the material had a special appeal to those in her circle, said Ladd, who was raised a Mormon.
"A lot of times people in this town who are very successful are left with a feeling of 'Is this all there is?'" she said.
The heightened profile of kabbalah meant enormous growth, but precisely how much is difficult to say. The parent organization, Kabbalah Centre International, was granted tax-exempt status as a church in 1999 and stopped filing returns.
The center's assets grew from $20 million in 1998, the year after Madonna went public with her ties to kabbalah, to more than $260 million by 2009, according to the resume of a former chief financial officer and tax returns the center and affiliated organizations filed before becoming exempt.
The center's revenue sources include fees for classes and sales of merchandise such as candles, red-string bracelets that the center says will ward off evil, and bottled water long touted as having healing powers.