WHEN THE Plough & Stars first opened, in 1969, Neil Armstrong had just set foot on the moon. The Manson gang had murdered Sharon Tate. The Vietnam War was in full swing, and kids from all over the country converged on the Woodstock Music and Arts Fair. Cambridge had become a destination for America’s cultural refugees: hippies, commies, cop haters, drug lovers, anarchists, nudists, and artist-terrorists swarmed the city like an invading army. The Plough soon found itself at the center of this countercultural jamboree.

Barry Rund — the shaven-headed, bushy-browed Sherman tank of a bartender — has worked at the Plough for 27 years. He recalls breaking up a fight that erupted, back in those early days, when one guy called another a Trotskyite.

And the bar itself represented a minor revolution. Before the Plough opened, 912 Mass Ave had been occupied by a neighborhood watering hole called the Elite Spa — though there was nothing elite or spa-like about it. The Elite was, in the words of one local, " a seedy tap room where postal workers gathered to spit on the floor. "

The Plough’s patrons weren’t necessarily more refined than their predecessors. Regulars can still recall Dick, a reported drug dealer who lived in a local commune called Casa Verde (where, according to lore, his false teeth still lie interred beneath the soil, having been buried there by his dog). By all accounts, Dick was an extravagantly disagreeable man, and he was very particular about where he stood at the bar. Once, when a guy refused to step aside so Dick could take his usual place, the agitated dealer waited outside, arms swinging at his sides " like Wyatt Earp, " until he grew bored and retired once more to Casa Verde.

The likes of Dick notwithstanding, the Plough quickly distinguished itself from other neighborhood bars. Though the city already teemed with drab Irish-American beer-and-shot joints, the Plough was the first to introduce an Anglo-Irish pub sensibility into the mix, establishing the bar as a place where you went not only to slake your alcoholism and apply another coat of tar to your lungs, but also to read, listen to music, and exchange ideas. From the get-go, the Plough became a hotbed of booze-fueled intellectualism.

Peter O’Malley, an early Plough bartender, epitomized this new spirit. O’Malley was outspoken, freethinking, robust of beard and temperament, and an avid didact. When he wasn’t building boats or delivering a critique of experimental literature, O’Malley pursued a music degree at Berklee, and he was given to playing the obscure works of classical composers during his shifts. Often he would challenge his customers: anyone who could name the composer got a free pint. Ever the poet, O’Malley early on characterized the Plough as " a place where you can meet people with failings more glamorous than your own. "

Within a few years of the bar’s opening, staffers of the Cambridge Phoenix were holding their weekly meetings there, as were the founding members of the now-renowned literary journal Ploughshares. Indeed, so intimate was the Plough-Ploughshares relationship that the journal took its name from the bar. And the connection looms large to this day: a recent Philadelphia Inquirer story on Ploughshares’ 30th anniversary, for instance, featured a large photograph of DeWitt Henry, one of the journal’s founders, with the caption: born in a bar.

" It was a rowdy place, but it was rowdy with culture, " says Henry of the Plough’s early years. " It was that idea of the pub being a cultural center rather than just a watering hole, of the writer being not an antisocial dreamer but a part of society, the idea that there is not a disconnect between highbrow and lowbrow. There was a dream of a voicing of a new deep culture, of art being populist, a function of interesting people rather than necessarily educated or privileged people. "

Sure enough, those early years saw all sorts of interesting people from all sorts of social backgrounds sipping the Plough’s 60-cent drafts. The bar became such a melting pot that it was often difficult to tell the eggheads from the roughnecks, as Barry discovered when he ejected one rowdy customer. " He was drunk and acting ridiculous, " Barry recalls. " He was standing on a table spouting what was probably wonderful poetry. I said, ‘You have to get off the table,’ but he wouldn’t, so I threw him out. I didn’t know who he was. I knew who Lawrence Ferlinghetti was, but I didn’t know he was Lawrence Ferlinghetti. "

Other writers had better luck at the Plough: Philip Roth drank and avoided the wrath of Barry; David Mamet wrote in quiet anonymity; Seamus Heaney behaved impeccably. But it wasn’t just the literati who took a shine to the Plough. Irish politician John Hume drank at the bar a couple of times. Ken Reeves is a long-time regular. In 1998, State Representative Jarrett Barrios — who worked at the Plough in the late ’80s — kicked off his campaign there.

Scientists, too, have often sought inspiration at the bottom of a Plough & Stars glass. One group of MIT physicists used to gather at the Plough to discuss their discovery of the so-called Norton Rings — bands of human urine and fecal particles that orbit the earth. And then there was Richard, a MacArthur Fellow who was developing technology to transform light into energy. One night, Richard rushed into the Plough, leapt onto a table, and held a box up to one of the spotlights, thereby inflating a large plastic penis. Barry, unmoved, told Richard to get off the table.

The Plough cemented its role as a cultural hotspot when, in 1975, it became the first bar in the area to host afternoon jazz sessions, featuring the music of the late Bunny Smith. Before long, it was not uncommon to find Bonnie Raitt tapping her feet to Spider John Koerner and John Lincoln Wright. In the intervening years, the Plough has emerged as an important music venue, a breeding ground for such up-and-coming local talents as Treat Her Right, Ray Bonneville, the Bad Art Ensemble, the Bag Boys, G. Love & Special Sauce, Mr. Airplane Man, the Ray Corvair Trio, and Red Chord.

Despite its successes, though, you wouldn’t describe the Plough as an ideal venue for live music. For one thing, there is no stage — bands play next to the restrooms, in such a tight spot that in order to go for a pee customers must push their way past the musicians. And yet no one seems to mind this arrangement. " That’s why I love the place, " says one local musician. " In a split second you can go from being an audience member to leader of the band. "

But then it’s a long-time tradition at the Plough to find virtue in necessity. In the early ’80s, neighborhood complaints led management to outlaw drums. To get around the ban, Billy Conway, the Treat Her Right drummer, would stamp on the floor and hit a railing with his sticks. These distinctive clicks and thumps became an integral part of the band’s sound.

But if you ask people for their favorite Plough musical moment, you’ll likely hear the name Mark Sandman, the Morphine frontman who, according to some, owed much of his later success to his early Plough sessions. " I think Mark exercised a lot of his creative muscle here, " says Morphine saxophonist Dana Colley. " He needed a place to showcase his material that allowed him enough freedom to be able to wing it. The Plough was a place for all of us to work our shit out. "

When he wasn’t playing at the Plough, Sandman could often be found having a quiet drink there — though he rarely remained quiet for long. " He would jump up and start singing, " says Colley, " or just deliver one of those amazing narratives that could only have come from Mark. " For many, the Plough is forever linked with the memory of Mark Sandman — who died of a heart attack in 1999 at the age of 46. " It was, " says Scott Getchell of the Bad Art Ensemble, " the last place I saw him alive. "

BECAUSE OF the popularity of its music, the Plough at night can get so crowded it would make a sardine wince. But six afternoons a week, the bar is transformed into a quiet little bistro, complete with red-checkered tablecloths, glasses of white wine, and a well-dressed, well-behaved clientele.

To say the Plough serves bar food is a little like saying Mozart dabbled in music. In the 30 years it’s been serving lunch, the Plough has employed a series of absurdly talented chefs. There was Marie Stackpole, who made fantastic stews and a killer meatloaf. Then came Yasmine Healy, known for her fusion of Middle Eastern and Irish cuisine. After Yasmine came the great Johnny Levins, who cooked up wickedly spicy Caribbean food. Then there was a " very radical " chef named Mark Usawich, whose specialty was nouvelle cuisine. Today, the chef is Jim Seary. " His food’s eclectic, " says Ken Reeves. " He puts together combinations of cooking styles. He gives you traditional favorites in a different skin and that makes them wonderful. "

And if your taste runs more to the liquid lunch, the Plough still serves the best pint of Guinness in town.

Not all afternoons at the Plough are tranquil bistro affairs, however. In 1990, the bar became the first in the area to start showing live English League football (i.e., soccer) matches, and when one of these games is on, the Plough is filled with a swirl of color and smoke, a clutter of tightly huddled beer glasses, and an awful lot of people using the word " wanker. " But occasionally, you will walk in and the bar will be as silent as a crypt, faces turned up toward the television screens with expressions of real grief.

The Liverpool manager Bill Shankly once remarked that football is not a matter of life or death — the game, he said, is more important than that. Speak to any of the Plough’s football enthusiasts and you’ll understand what he meant. Gavin, a rabidly faithful Manchester United fan, once said that he was thinking of getting United’s logo tattooed on his arm. " Is that a good idea? " asked a bystander. " What about when you’re 40? What are you going to say when your son asks why you have that tattoo on your arm? " Without missing a beat, Gavin responded, " I’ll say, ‘Same reason you have it tattooed on your arm, son.’  "

Sometimes the Plough will show a match involving the English national team, and sometimes (okay, often) England will lose. When this happens, the bar’s Irish patrons will needle us English guys a bit. But it’s always a good-natured needling. Despite the fact that the Plough & Stars took its name from a Sean O’Casey play about the Easter Rebellion, and despite the fact that in the early days there was a no tea served here sign above the bar, there is never any real antagonism between the Plough’s English and Irish patrons. Most of the time it’s easy to forget that you’re even in an Irish bar.

There’s a story about an Irish-American guy who approached George one day and demanded to know why the Plough didn’t have Irish music playing. " If this was an Irish bar, " the man said, " there’d be Irish music. " Unruffled, George replied, " In Dublin there are no Irish bars, just bars. This is just a bar. "