He was perhaps the greatest theorist of all time, enjoyed playing the violin and was a good shot with a squirt gun. He accurately foretold the findings of today's astrophysics a half century before technology could catch up with his insights, and he had trouble at times finding his front door.

Albert Einstein is being lauded throughout the world in this centennial of his birth (March 14, 1879) as the giant of theoretical physics, a possessor of true genius, author, philosopher, humanitarian. But in this New Jersey community where he spent his last decades, an additional affection is expressed for Einstein the man -- his warmth, kindness, childlike sense of play, even his not infrequent absentmindedness.

And amid the outpouring of praise for the late Nobel Prize winner, friends often note that praise was one thing Einstein enduringly hesitated to accept during his life, although he bore his fame patiently.

"He was the most humble, genuinely humble, man you could possibly meet," declares one acquaintance.

IN 1933, as the political situation worsened in Germany, Einstein settled in this academically oriented town. He acquired a modest residence on quiet Mercer Street with his step-daughter Margot and secretary Helen Dukas, who still live there, and his wife Elsa (who died in 1936).

It was one mile to his office at the Institute for Advanced Study where his "professorship" allowed him to continue his work. Einstein walked the distance every day in good weather and was soon encountered by other users of the tree-shaded thoroughfares -- the neighborhood children.

Various youngsters befriended "old Mr. Einstein" (or vice versa) during his later years. One boy met him punctually at 4 o'clock on his return walk, traded jokes with him and was often taken home to view the scientist's chemistry equipment while Einsein sat with a pad of paper on his knee and "wrote with his funny numbers." Before his death on April 18, 1955, Einstein was pursuing a Unified Field Theory encompassing gravity, magnetism and atomic energy.

Two other boys discovered that the founder of the Special Theory of Relativity possessed considerable prowess with a water pistol. Each summer they would provide themselves and Einstein with squirt guns. He was a good shot both in pace-and-turn dueling and in cowboy-style straight draw.

Several stories persist about Einstein helping children with their arithmetic homework, but these are probably apocryphal. He turned down one such request with the gentle explanation that it would not be fair.

IN PRINCETON, with its numerous amateur musicians, Einstein is much associated with his violin. He enjoyed playing on weekends with associates from the Institute for Advanced Study or as part of local amateur chamber ensembles.

Always mannerly and considerate when receiving visitors, he simply tolerated many social forms. Once, while patiently sitting through a long after-dinner speech, he whispered to a friend, "I think I have a new definition of infinity." He grooming was casual, even careless, and now legend -- bushy, untrimmed hair and mustache, worn sweaters and baggy pants made him a local character.

A theorist, Einstein did no empirical research, but worked out experiments and formulations in his mind. Intense concentration on abstract problems sometimes yielded, however, unexpected and unpublishable results. One day, while walking along lost in thought, Einstein came upon an open street construction trench and tumbled in. Local photographer Alan Richards happened by and snapped the picture. Einstein begged Richards not to print the photo, and Richards replied by handing Einstein his film on the spot. For years afterward, Einstein was the subject of many informal, but more complimentary, portraits by the photographer.

George Olsen, of nearby Belle Mead, N.J., recalls that Einstein's front door was painted red to aid the scientist in finding his way home. "He was ending up in everyone else's house on the street," says Olsen, who came in contact with the professor in the course of several second jobs he worked while bringing up his family.

Olsen was doing routine maintenance on the Einsteins' oil furnace one afternoon while the physicist was also in the basement, cheerfully working on a sculpture in stone. "I think it was supposed to be Franklin Roosevelt," says Olsen. He noticed Einstein's tools. "He was using chisels that were real dime store quality. I didn't know how he was making a dent in that granite, but he was."

Meanwhile, Margot Einstein, with characteristic old world hospitality, brought the visiting worker a glass of lemonade.

YET DESPITE a reputation as the quintessential absent-minded professor, Einstein was hardly out of touch with the realities, often grim, of the academic and political world.

Psychologist Hadley Cantril, who lived a few doors away on Mercer Street, once demonstrated a model of his now famous trapezoidal room for Einstein. The physicist grasped at once the psychological and philosophical import of the perceptual illusions caused by the seemingly square interior. Er. Cantril remarked that he was frustrated by the refusal of fellow psychologists to take his findings seriously. Einstein conforted Cantril by noting, "I have learned, don't waste time trying to convince your colleagues."

Albert (Tad) Cantril, the late psychologist's son, remembers how Einstein disdained, sometimes with vehemence, attempts to venerate him. Tad's mother had wished that her young son and daughter might each have an autographed book as a memento of their great neighbor. So she called at Einstein's home and spoke with his secretary.

"She was right in the middle of explaining her visit to Miss Dukas," says Cantril, "and was talking about Einstein's being a great man when he came downstairs."

Hearing the conversation, at that juncture, the usually patient and gentle Einstein exploded in anger. "This is the cult of personality!" he shouted. "This is what breeds Hitlers and Stalins!

At that moment, a visiting colleague of Einstein's interceded and asked Mrs. Cantril to leave the books. She departed, "feeling about 2 inches high," but Einstein did autograph the volumes and return them.

Knowing how he felt about adulation causes many of his friends and former neighbors in Princeton to ponder how Einstein would react to certain of the centennial commemorations, such as the giant-scale Einstein statue planned for the National Academy of Sciences.

One occasion when he did not receive adulation, or even any notice, serves to reveal human nature and the place of an immortal like Albert Einstein in the events of everyday life.

George Olsen remembers working many evenings as an usher at the Princeton Playhouse movie theater when Einstein and his stepdaughter attended the shows. One night, standing in the lobby while the film played, Olsen noticed an expectant crowd gathering outside.

"I thought they were coming to see Albert Einstein and give him a big reception," he recalls. "Then the movie let out. Einstein and his daughter came out and nobody said boo to them. They walked away and I don't think anybody noticed him."

The mystery was explained moments later when pop singer Johnie Ray, visiting in town that night, emerged from the theater to a frenzy of screams. While the individual who gave humanity monumental insights into the nature of the universe and time disappeared down the street, the adoring crowd flocked around its star of the moment.

Had Dr. Albert Einstein been aware of the scene he was leaving a relative distance behind him, he would no doubt have smiled gently.

Most of us will never fully understand the complex ideas that Albert Einstein gave the world. But we can glimpse the outlines of his genius and imagine its awesome dimensions. To appreciate Einstein on the centennial of his birth is to celebrate the potential of the human mind .