For more than two decades, they had been known as "The Two." They were soft-spoken and secretive, a nurse and one of her former patients. They called themselves Bo and Peep, or sometimes Tiddly and Wink, or even Winnie and Pooh.

Marshall Herff Applewhite and Bonnie Lu Trousdale Nettles had a knack for winning publicity. In 1975, they made it onto Walter Cronkite's newscast, "a group of earthlings who believe they're on their way to a rendezvous" with a rocket ship from outer space.

According to academic studies and news accounts, he was a music professor who had sung 15 roles with the Houston Grand Opera and was said to resemble Mister Rogers in manner and voice. She had left medicine to become an astrologer, and left her family to join Applewhite in a spiritual journey. Both were once dedicated Christians. And both came to believe that they were aliens from the "next level," sent to Earth to find converts who would join them in a return to outer space.

Nettles died sometime in the last few years. But Applewhite emerged last night as the apparent leader of Heaven's Gate, or Total Overcomers Anonymous Monastery as it was sometimes called, the group whose members committed mass suicide in Rancho Santa Fe this week. Whether he died with his followers had not been determined.

The man who for many years was seen in videotapes as a white-haired harbinger of celestial salvation made his final pitch in the tape that announced this week's suicides. Now appearing with a shaved head, Applewhite said, "You can follow us, but you cannot stay here and follow us."

According to academic studies of Bo and Peep and H.I.M. (Human Individual Metamorphosis), the group they led in the 1970s, Applewhite and his followers have been holding meetings, publishing tracts and recruiting members throughout the Midwest and West for more than two decades.

His message throughout has been unchanging: To be saved from Lucifer, human beings must give up all earthly pleasures. And they must be ready to leave this planet on a UFO that would whisk them to a new world, a better life.

"We're going to be murdered . . ." Applewhite told a Texas radio reporter in 1974. "And when we are, after 3 1/2 days, we're going to walk out" into life in the next level above human.

Twenty years later, Applewhite -- now known variously as Do, the Older Member, and the Present Representative -- would write that he was "in the same position to today's society as was the One that was in Jesus."

Bo and Peep's early years preaching the promise of life in outer space won them a certain notoriety. Lapsed members of the group complained in several news accounts in the 1970s that they had been bilked of thousands of dollars that they had paid Applewhite and Nettles for "educational" training. According to a 1976 New York Times Magazine article about the unmarried couple, one defector from the group filed a fraud complaint in Los Angeles and others brought their complaints to news reporters.

The Two -- named for the two witnesses of the End Times in the Book of Revelation -- were arrested in 1974; Applewhite plead guilty to a car theft charge and served four months in prison, according to that 1975 CBS "Evening News" report. The charges against Nettles were dropped.

Another defector, Paul Groll, told Time magazine in 1979 that Bo and Peep's flock once numbered 200 people who had ditched jobs, families and possessions to join the self-styled extraterrestrial shepherds from Texas.

Groll portrayed Applewhite and Nettles as stern disciplinarians who required their followers to report at the command tent at 12-minute intervals throughout the day.

That and similar stories from other former members contrasted sharply with a more benign account offered by a University of Montana sociologist who said he infiltrated Bo and Peep's group in 1975 and later interviewed former members. In an interview in the Chicago Tribune in 1994, Robert Balch said Heaven's Gate did not strike him as "a dangerous cult. It is not in the mold of the Charles Manson family, Jim Jones' People's Temple or David Koresh's Branch Davidians," he said then.

Wandering groups of spiritual searchers were a commonplace in the turmoil of the early 1970s. According to news accounts of the period, many of the people who joined Bo and Peep had already tried yoga, Zen, Scientology, astrology, among others.

Applewhite was apparently disheartened by the ridicule to which he was treated after his bath of publicity in the mid-'70s. According to "Beyond Human," a 1996 book published by Heaven's Gate and written in part by Do, the news media "typically hastily" judged the group, "tagging them the UFO Cult,' because of their expectation of leaving aboard a spacecraft at the completion of their task."

As quickly as they had entered the limelight, The Two seemed to vanish for 16 years. From 1976 until 1992, the Heaven's Gate book says, "we were very much lifted out' of this world -- literally."

Applewhite emerged from those years of seclusion determined to reach a broader public. In 1992, he produced a series of videos and broadcast them by satellite. But the book says the videos brought into Heaven's Gate "almost entirely our own lost sheep' -- that is, crew members who had previously dropped away" from the group.

Next, Applewhite took out a one-third page ad in USA Today on May 27, 1993, headlined " UFO Cult' Resurfaces With Final Offer." The long, small-type treatise announced that "Earth's present civilization' is about to be recycled."

Then, in January 1994, Applewhite and his followers "sold all of our worldly possessions except for a few cars and changes of clothing," and, according to the book, set out across the country to hold public meetings and conduct media interviews.

News accounts of that national tour describe young followers who dressed exactly alike, who gave up their own names, cut off ties to their families, and renounced all forms of sexuality.

Despite the group's newspaper ad, videotaped lectures, and chatty, science fiction-style essays posted all over the Internet, Applewhite and his group have conducted their earthly endeavors with extreme -- and often clever -- stealth.

The group used post office boxes and phony addresses in Colorado, Texas, New Mexico, Arizona and Minnesota. When Heaven's Gate set up its domain on the Internet, it provided contacts that trace back to a Ramada Inn in Denver and Internet service providers in Fayetteville, Tenn.

One of the contacts the group provided, Ben Guiat, turns out to be the name of a type font; Guiat's e-mail address, cleverly enough, is font@cris.com. Another contact provided by the group has a telephone number that connects to a California company that will try to reunite long-lost friends for a $69.95 search fee.

Ed Deppy, president of Spacestar Communications, the Minnesota company that provided Internet access to Heaven's Gate for the past year, said he was approached by a woman who called herself Sister Francis Michael. (In a 1972 interview published by the Houston Post, Nettles said her assistant in her astrological work was a Brother Francis who had died in 1818.)

But the phone number Sister Michael gave Deppy leads to an unidentified voice mailbox and the address she provided is a grassy field near a Best Buy store in Burnsville, Minn.

In 1995, according to the Heaven's Gate book, Do took his message to the Internet, where he again met with "ridicule, hostility or both." This, the book says, "was the signal to us to begin our preparations to return home.' "

In October 1996, Applewhite produced a videotape that he entitled, "Planet About to be Recycled. Your Only Chance to Survive -- Leave With Us." The last change in the Heaven's Gate Web page was made early Monday, Deppy said. It was the addition of a flashing "Red Alert" notice warning that the comet Hale-Bopp "brings closure to Heaven's Gate." CAPTION: (Photo ran on page A01) Marshall Herff Applewhite led the cult he founded more than two decades ago with Bonnie Lu Trousdale Nettles, who died in the last few years.