The recent 50th anniversary of the Broadway opening of West Side Story drew many New Yorkers, both current and former, to nostalgic reflection. I was no exception, for it happens to be my favorite musical bar none, and I would expect similar sentiments from any child of the Upper West Side. Rest assured that any local who doesn't share my feelings on the matter is senile, ignorant or lying. After all, how could anyone not take special pride in a musical for the ages, where the dancing, singing and rumbling all take place against a backdrop of our very own streets? For those who don't know, the story starts with two opposing gangs: the Jets, who are white Anglos, and the Sharks, of Puerto Rican provenance. Tony, the Jets ex-gang leader, falls for Maria, the sister of Bernardo, leader of the Sharks. The story ends in tragedy. Romeo & Juliet for the 20th century, they said. The tributes are flowing, with lectures held around town, a major exhibit at the Library of Congress, and commentary on radio and in newspapers, which have all added information and perspective for a national audience too young to tell a Jet from a Shark. Even I managed to learn a few new things about the musical. For instance, Brian Wise of The New York Sun relates that the play was originally conceived by director/choreographer Jerome Robbins as "East Side Story," with a Jewish girl from the Lower East Side and Catholic boy from the Village as the protagonists. Then on the drive home from work last week, NPR framed the production for listeners within the darker context of the McCarthy Era: How strange that in the early 1950s Robbins had actually named the names of his three future partners, Leonard Bernstein (composer), Stephen Sondheim (lyricist) and Arthur Lorents (playwright) to the House Un-American Committee. Even stranger was the ability of the named three to transcend their understandable animosity toward Robbins and actually collaborate with him. Practical and professional considerations no doubt prevailed in their calculations, since they must have sensed that this particular partnership could be something huge. STILL, WHAT I've heard and read on the subject, though interesting, comes off as distant and academic, which is just not enough. Those who wish a more street-level perspective should interview someone who breathed the air the Jets and Sharks breathed. Say, someone like me. But before expounding on the play's merits, Its vital to know the qualifications that endow me with such insight. First of all, as a creature of the neighborhood, I'm bound to possess more insight that anyone who isn't. And bearing witness to the messy and dangerous environment that prevailed around the time of the musical's 20th anniversary in 1977 lends more substance to my observations. Secondly, I share a Jewish perspective on the two gangs with the musical's creators, which allows for a certain dispassionate appreciation of both sides. Indeed, my own understanding may surpass that of the creators, since I possess the distinction of having been mugged by hoodlums both Puerto Rican and white. But the best reason I'll leave for the end. As some may remember, the seventies were not exactly a period of zenith for this town. However, contrary to popular memory, the decline into the chaos of the time was gradual and decades-long, not a sudden plunge. Writing in the October issue of Commentary, Hillel Halkin recalls a confrontation with an Irish gang on West End Ave who forced him to blow his nose in his yarmulke - and that was in lilywhite 1949, eight years before the musical's debut. And in 1958 (within months of the play's opening) The New York Times' Harrison Salisbury reported on a dramatic multi-year rise in juvenile crime, wondering how a progressive city such as New York was failing to solve the problem. BY THE late '50s, dozens of gangs of many flavors roamed the city's streets. In fact, one of the actors who played a Jet in the original production learned how to catcall and whistle from his very own local gang, whose turf was west 80th Street. Even Jane Jacobs, scourge of Robert Moses and champion of human scale neighborhoods, was moved to describe the Upper West Side as a "surly slum." By the mid seventies, most locals took to triple-locking themselves into their stuffy rent-controlled apartments for the night, an eminently sensible strategy considering the state of affairs on the sidewalks below. Dusk was the cue for drunks, pushers, addicts and other assorted losers to leave their welfare hotels and strut their stuff. In a 1976 article in the Times Sunday magazine, Collette Dowling described the not uncommon scene of "bands of transvestitesâ€¦clattering on their high platform shoes, their skinny nipples twinking (sic) under bright satin shirts." The procession often continued with mobs of disco-era Cossaks strutting down Broadway, boomboxes ablast. Even the Sharks and the Jets would have been beside themselves. IN 1979, I was mugged by characters right out of West Side Story. That Pesach, two friends and I were confronted in the park by a mob of Puerto Rican evildoers. Only by our shtetl-sharpened and ghetto-honed survival wits (and the timely appearance of a squad car) were we able to escape by the skin of our tukhises. Then on Succot I found myself surrounded on the street in broad daylight by a gang of latter-day Jets, teen-aged crusaders who taunted me with their lit cigarettes. I somehow got away from that too. NOW I'M sure that if any doubts still lurk in the reader's mind as to my suitability to offer comment on this Golden Anniversary of the West Side Story, they've all been allayed. Oh yes, there's one final reason I deserve a voice on this matter, the one I left for the end. The very year I was mugged by both the Jets and the Sharks, our yeshiva high school drama club staged the musical, and I played Chino, a young Shark tough who ends up killing Tony, Maria's love interest. Finally, I was a part of the action, and not just an outsider looking in or a hapless, harassed victim. I must confess, though, to one important difference between Chino and me. Our production couldn't be staged in dangerous Riverside Park or on the mean West Side streets where the Jets and Sharks lived. Our stage was an artfully-crafted ersatz slum across town, amid the silk-stocking safety of Park Avenue and 85th. I suppose one could contend it was more of an East Side Story. The writer is a New York-based author and research analyst. He is now writing a graphic novel about life and loss on the Lower East Side.