PERHAPS like the Shining Path insurgency, the doors leading into the plain prison building at the Callao naval base near Lima are simple, but deceptively strong. Inside is the small room where the man who aspired to bring a socialist revolution to this country will be held for the rest of his life. Captured three years ago today, Shining Path (El Sendero Luminoso) leader Abimael Guzman Reynoso is now thin and pale from lack of sunlight. Reportedly he gets one hour of light a day to read or exercise. This former university professor who eluded authorities for a dozen years now reads comic books. But is Shining Path, the Maoist guerrilla organization Mr. Guzman founded in 1960 that has been responsible for 30,000 deaths in the last 15 years, similarly faltering? New rebellion Six months ago, most observers said the Shining Path movement was itself all but dead. Its activities were limited to a few odd bombings or maneuvers in remote jungle areas. The force that had once terrorized the nation had shriveled to less than a fifth of its former size. During elections earlier this year, President Alberto Fujimori, who had recorded high approval ratings on the strength of severely pruning back terrorist violence, promised to have the group wiped out by his July 28 inauguration. The group again rose up violently, however. After a two-year absence in Lima, the Shining Path bombed a major tourist hotel and casino in May, killing four and injuring 40. A month later, the house of the Congress's vice president was bombed. Then a police substation was strafed and a water tower destroyed. Guzman's successor, Oscar Ramirez Duran - best known as Comrade Feliciano - has vowed to continue the fight. In the provinces, a small town was occupied overnight, columns of soldiers were attacked and nearly 350 people killed between April and July in more than three-dozen attacks. By June, Mr. Fujimori had backed away from his promise to eliminate the group. ''The Shining Path isn't what it once was, and it may never be, but it can still cause a great deal of trouble and, more importantly, there's a lot of potential for much more than that,'' says Lima political scientist Gerard Maton, an expert on the group. Like most experts, Mr. Maton attributes the group's early successes, starting in 1980, to the government's failure to take the terrorist threat seriously. For many years, he says, the group that was founded at an obscure agrarian university near the Andean town of Ayacucho limited its influence to mountain areas. In 1990, the group made its most serious and successful push for power. Within two years, signature car bombs were regular occurrences in the best parts of Lima, and many predicted the government's imminent collapse. When Guzman was captured late in 1992, Lima's streets flooded with joyful Peruvians who saw the capture as the beginning of the end of the violence. The violence did slow considerably. The death toll, 3,101 in 1992, dropped to 646 last year, a number that may have already been surpassed this year. But in the streets of many of the Shining Path's mountain strongholds, buildings are freshly painted with slogans such as ''Long live the people's party! Long live the armed struggle!'' Many say that the Shining Path, which, according to local news reports, has recently stepped up its recruiting campaign in many poorer areas, can only be completely eliminated with an improved economy. That is just beginning to happen. President Fujimori, who took office in 1990, is credited with major improvements in a country on the brink of economic collapse. In 1992, inflation was 7,000 percent. This year, it's projected to be 13 percent. But Peru has a long way to go. Almost half of its 23 million inhabitants still live in poverty. ''Kids who were five in 1980 are 20 now, and they've lived their whole lives poor, hungry, and in a state of war,'' says retired Gen. Sinecio Jarama, who was charged at one time with fighting the insurgency. Young rebels are ready In Ayacucho, the Andean birthplace of Shining Path, the revolution still shines as brightly as ever in the eyes of two young foot soldiers. Cousins German and Eder, who gave only their first names, say the day will come when the leaders of their movement will sit in power. The two agreed to talk briefly in a small restaurant near the center of Ayacucho. ''The government here and now is forgetting almost all of Peru,'' says Eder. ''The people who aren't in Lima, who aren't in positions of power, it's as if to the government they aren't even in Peru.'' German agrees. ''It's easy to find people not pleased with the government,'' he says. ''Just ask a campesino [peasant] how [Fujimori] has helped him. Is he better off now? Can his children find good jobs in the cities? When you hear 'no,' that means the revolution [is coming].''