One morning earlier this month, the pilot of a Gulfstream jet radioed a tiny airfield high in the Colorado mountains, asking for permission to land. On board the private plane, which had taken off two hours earlier, were two senior members of the controversial Church of Scientology. As it taxied to a halt at the end of the runway at Telluride Airport, the emissaries were met by a blacked-out sports utility vehicle and driven three miles to the secluded 250-acre estate of actor Tom Cruise. Their mission was not, however, to minister to the Hollywood superstar. Instead, their appointment was...