The two-layer cake had a fake stick of dynamite for a candle, a yellow hammer and sickle painted on the red wax. The words on the cake said: "Long Life, Mr. President."

It was a birthday party for the leader of Peru's Shining Path, the most dogmatic and dangerous guerrilla group in South America.He wasn't there. Abimael Guzman, known to his followers as "Presidente Gonzalo" and the "Fourth Sword of Marxism" - after Marx, Lenin and Mao - has not been seen in public since 1979.

Guzman's 56th birthday was Dec. 3. About 30 rebel inmates of Lurigancho prison on Lima's slum-ridden eastern outskirts gathered the day before to wish him a long life.

"We are celebrating the anniversary of the birth of the greatest living Communist on the face of the Earth," said a Shining Path political officer who identified himself only as Comrade Fausto.

It was visitors day. As the rebel inmates watched, almost with reverence, Fausto called a 10-year-old boy, the son of a prisoner, to the front of the room. He gave him a carved wooden rifle to hold and asked him to blow out the candle on Guzman's cake.

"It's chocolate inside," Fausto said, smiling broadly. "The flavor our president likes."

At least 20,000 people have been slain since the Maoist guerrilla group began its insurrection in 1980. Most of the victims have been highland peasants who were killed either by the rebels for resisting them or by security forces who suspect them of rebel sympathies.

About 200,000 refugees have streamed into the cities from remote villages. Guzman's followers have done more than $16 billion in damage.

Rumors spread in recent years that Guzman, a former philosophy professor, was ill or dead, but were discounted after police raided a rebel safehouse in an upper-class Lima neighborhood in June.

They found Guzman's thick eyeglasses, a wig and sleeping pills in a bedroom. But the elusive leader of the Shining Path slipped away before they arrived.

The escape was bad news for Alberto Fujimori, who became president of Peru on July 28.

Unless Fujimori devises an effective strategy against Guzman, analysts say, he probably won't be able to pull Peru out of its economic and social crisis.

Gustavo Gorriti, author of a new book on the rebel group, calls Guzman "democracy's most formidable enemy in South America, and probably in the hemisphere."

Guzman's followers have a fierce commitment to him.

The birthday celebration included recitations of poems praising the "armed struggle" and revolutionary chants in honor of Guzman.

Although Guzman's writings are charged with violence, former students and faculty colleagues remember him as a quiet intellectual, courteous and gentle, an excellent teacher who went to great lengths to communicate his ideas.

Guzman taught at the University of Huamanga in Ayacucho, high in the Andes 230 miles southeast of Lima, from 1963 through most of the 1970s.

"He was the kind of person who, if he saw an old woman who wanted to cross the street, would go get her and help her across," said Luis Guillermo Lumbreras.