AS AN OLDTIMER to the Square might tell it, all the real Activism has gone out of Harvard Square. Four years ago the Square was practically mad with New Left Happening: its street corners busy with politicos pamphleteering, its restaurants busy with politicos planning, its street life rich with political street theater. Sporadically, its Action would flare up in virtually all forms of street fighting, in everything from noisy portest to out and out rioting. Nobody is really sure where that old Activism disappeared to, and nobody really wants to believe that it died somewhere. You still heat talk about the Revolution. But the air just isn't as heavy with such talk as it once was.

Anyway, the Square is still ahustle with traces of times gone by. Local craftsmen sell their art on the street; street people do a business in panhandling; street haw kers make their bread by quarters, with the youth oriented Real Paper or Phoenix; freaks make music on the sidewalks: and all of them hand out at one time or another in the heart of the Square, the plaza in front of Holyoke Center. The way they dress hasn't changed much--it's still tattered jeans. But the outfit is no longer so easily readable as a political statement; it is worn rather as a hanging on to a faded out past, as if the old collectivist politics had somehow personalized.

And what has grown up in the gap left by their passing is a commercialized Harvard Square: retail chains have replaced some of the older smaller storefronts, high rises have been built to make room for new business transplants, and Brattle Square has sprawled out into a polyethelene looking shopping place, high priced to match its glass rimmed surface.

Though it's got a new face, the Square is still a place where anything can happen. So much for introductions. Here is, humbly, a student's guide to the Square, dedicated to the meager budget.

Snacks

The Complaint is so old that hearing it can make you sicker than the reason for its being. Anyway you will probably not last long on Union food since it will bring nausea into your guts and mess up you life.

Now the best places for sandwiches are Elsie's (at Mount Auburn St. and Holyoke St.) and Tommy's (60 Mt. Auburn St.). Elsie's specializes in huge delicatessen sandwiches; Tommy's has subs just about as big, first class pinball, and quiet toned jukebox--all suited to the midnight muncher. The 24 Restaurant, next door to Elsie's has had more facelifts in the last few years than practically any place around, and now it is better than ever: Greek salads heavy with feta cheeze and cheezy thick Greek pizza, the kind that leaves strings dangling when you snag a bite.

For fancier and more expensive sandwiches and a much larger menu to choose from, try the Midget Delicatessen (1712 Mass Ave., near the Radcliffe dormitories). Roy Rogers (1613 Mass Ave.) is not worth much more than avoidance unless you have a penchant for pre-processes roast beef and the atmosphere of a bogus MacDonald's.

There are two restaurants in the Square devoted to hotdog cravers. The Underdog (6 Bow St., and prone to flooding on rainy days) has kosher hotdogs, multi-sized, -shaped, and -topped, with assorted garnishes, as well as bagels that are pretty good dressed up with their lox and cream cheese. ZumZum (9 Brattle St.), part of a small East coast chain, serves knockwurst, bratwurst, and bauernwurst, with very tasty potato salad. Remember to wash it down with their dark beer--it spikes the taste.

Bartley's Burger Cottage (1246 Mass Ave.) is hamburger kind of the Square. The Bun'n Burger is its basic simple, but the burgers grow ever more decorative with the Muenster Burger, the Super Pizzaburger, the Hawaii Pineapple Burger, the Texas Chiliburger and on ad nauseum.

The Hungry Persian (52 Boylston St.) or Hemispheres (on Mt. Aubrun next to Tommy's) cater to the more exotic palates. The Persian serves its sandwiches in hot Syrian bread, and the contents--mostly sliced and shredded cold cuts--are flavored with tahini sauce, filling for less than a dollar. Hemispheres serves a nice eggplant dip, the best roast beef in town and a baklava that has a foothold on that distinction.

The three pizza parlors in the Square don't turn out stuff too differently from each other, though experts will argue over the fine touches in the pedigree of each. They are Joe's (at the corner of Mass Ave. and Linden St.), the Pizza Pad (at the corner of Mt. Aubrun St. and Plympton St.) and Pinnochio's (74 Winthrop St:). Joe's seems to be the favorite of most.

Four ice cream parlors is perhaps a lot for a square. Brigham's (next to the Coop) gives you standard fare, Bailey's (21 Brattle St.) dresses it up with weight consciousless sauces, Baskin Robbins (1230 Mass Ave.) you must already know about, and the Spa (0 Brattle St.) is for health freaks.

For late breakfasts the Pewter Pot (3 Brattle St.) mixes up everything from fruity flavors to raisiny spices in its muffins. As You Like It (1326 Mass Ave.) serves you your standard American Man's breakfast, and Nornie B's (61 Church St.) had doughnuts to top off the sweet tooth's craving.

Supposedly, Joyce Chen's (302 Mass Ave. and 500 Memorial Dr.) is the place to go for Chinese food, but its prices are too high to rate it a place in this listing. The Hong Kong (1236 Mass Ave.) and Young and Yee (27 Church St.) are more reasonable--maybe they understand their clientele better.

Osaka (617 Concord Ave.) is not to be missed for Japanese finger lickin' sensations, but watch your prices because you're liable to go overboard. Its sushi, or raw fish, is worth the splurge--they say it's better than what Japan itself would give you. The teppanyaki or sukiyaki might be less strange to taste buds geared only to the Western way. The Korean dishes at Matsuya (1768a Mass Ave.) pull sore second, but that's no insult. The Tempura Hut (444 Portland St.) is for the Westerners at heart only.

A note for those with bulkier billfolds: the French food at Chez Jean (1 Shepard St.) tingles the taste of even those cosmopolitans finicky for delicacy. You couldn't say as much for Chez Dreyfus (44 Church St.), but there it is the customers that make the going or the gossiping good. President Bok eats there on his working days--how regularly that is is hard to say--and he tends to favor chopped sirloin with mushroom sauce (during a hot summer day?).

If you're still eating steaks--who is anymore with meat worth its weight in gold, a death toll in cholestorol build up, much less a good dose of bad vibes in hostility content?--you can get them and find the type that eats them at Barney's (22 Boylston St.) and Buddy's Sirloin Pit (across from the Brattle Theater). The Wursthaus affects a slight German accent, fine for families who aren't liable to notice the pretensions because they're busy, if they're normal Wasps, fighting. The headwaiter doesn't like students much anyway. For Mexican food that can sear your insides go to Casa Mexico (75 Winthrop St.): it's good but far from cheap--they've never heard to chili there. For the best Spanish food around Iruna (56 Boylston St.) is a must.

There are plenty of other restaurants neglected here due to lack of space; for now, chalk them up to experimentation.

Cafe life in the Square may not be any Paris in the twenties--rather it is a Boston brand of boardwalk watching, coffee sipping retreats from the Action that play at the cosmopolitan feeling of being above it all. The Pamplona (on Bow St. next to the Underdog) reverberates with the undertones of the heavies, of intellectual riffraff at its most sincere and heart of heart having it outs. Everybody eavesdrops, it is licensed voyeurism. The Window Shop (56 Brattle St.) is an outdoor cafe that provides a front row bleacher seat as to who's who at the Casablanca (where the preppies hang out for their booze). Grendel's Den (on Boylston St. across from the Hungry Persian) is a basement coffee house with great spicy shiskebab, an endless selection of the most select folk rock albums, and some of the most carelessly elegant counterculture waiters around.

Late night drinkers are going to be hard put to find a place that will see their bout to its finale--most of the bars close at 1 a.m. The Blue Parrot (123 Mt. Auburn St.) and The Idler (right underneath it) are for intimates or loners who like to do their boozing in quiet. Their sangria goes down as smoothly as lemonade and mellows your insides with a particularly warm high. Cronin's (114 Mt. Auburn St.) is a traditional Harvard beer guzzling haunt, but it should be avoided on principle--a waitresses' union protested the restaurant's miserable working conditions for who knows how long, and the owner fed their complaints with abusive intransigence.

Jack's is for the sort of noisy drinker who likes crowds so tight that his neighbor can feel his stomach gurgle. A Harvard alum runs the place--hopefully the fact that the place is jammed does not come out of any cultivation of the connection, be it conscious or unconscious. Rugby shirts are standard wear, and George Kimball, The Boston Phoenix's Gonzo sportswriter, loves the place. The Club Zircon (298 Beacon St.) has live rock--as well as Jack's--but a cover charge to boot.

Sadly to say, the Square has closed its all night restaurants, except for The 24 Restaurant, which will serve you pizzas and decent Greek food all night long Thursday through Saturday. On any other night the only place to go for munchies after 2 a.m. is Dunkin' Doughnuts (in Central Square); it is a short hitch, but at times thumbing it is putting your life on the line. Mondo's (in Haymarket Square in Boston) is well worth the trip if you have got a car. Clientele ranges from truck drivers to spiritual descendants of Oscar Wilde, denizens of the North End dressed in sunglasses. Fedoras, dark shirts and wide white ties sit elbow to elbow with shoulder length longhairs in tie died muscle shirts and jeans with plastic bags tucked in the pockets. Everybody loves the ham and eggs and the lurid murals.

The Square offers rather meager prospects vis a vis grassy sports on which to sleep off the night before, or the meal, and to while away the time in between. And seclusion vanishes like hotcakes. The banks of the river Charles are likely to be packed with sunners, sleepers or cavorters who make either difficult. I suppose nobody would object to nakedness if you felt that you really needed it, but I've never seen it. (Four years ago a group of Radcliffe women were arrested running around without any clothes on in front of a camera crew on the highway because the spectacle had created a traffic jam.) The Commons has yet to grow grass enough to protect you from the dirt beneath, and serious sunbathing in the Yard is practically like passing out a publicity still.

Movie Theaters

Movies in Cambridge are much cheaper than they are in Boston, where $4 is hardly considered outrageous; rather, they see it as the least you could do to advertise your affection for the movie moguls' latest packaged form of loyalty to the public upon which they depend for making movies. The Cambridge films may not be the most Now thing on the movie market, but they are rich in movie classics. The Orson Welles (1001 Mass Ave.) contains a film school and a restaurant, aside from its two theaters. Pick up a schedule because the Welles holds week long festivals at least one of which will be worth planning ahead for. Cambridge's other three theaters--the Brattle, the Harvard Square, and the Central are all under the same ownership. The Brattle specializes in classic, popular and auteur revivals--Cagney and Bogart will be big there this summer. Harvard Square usually features first run films about six months after their original distribution--so if you can't afford Tango now, or if you refuse on principle to pay the $4.50 asking price, wait a while; it won't be too long til you can see it under more reasonable conditions. The Central has two theaters in one building. One of them has been featuring virtually the same double show for about three years now, but it's Phillipe de Broca's "King of Hearts" that draws the crowds, and still to sellout capacity--why, I haven't the faintest. Some people say that it is funny, but it is a fool's form of funniness.

Clothing Stores

The Square has a reputation, judging from the scores of groupie locals that flood it on weekends, as an ask-for-it-we've-got-it gold mine. But its prices are fit for a gold rush town, booming sky high. There are small stores and boutiques galore--even year long residents don't exhaust them for interest. Central War Surplus (433 Mass Ave.) is the place to find durable blue jeans, bells, and work shirts, the sort of garb that has become the staple badge of student identity, collective and anonymous, a product of need rather than conspicuous consumption. Jeans and shirts decorated to dazzle the streets can be found practically anywhere in the Square: The Coop (1400 Mass Ave.), the two Slak Shacks (485 Mass Ave. and 59 Church St.), and The Lodge (opposite Bailey's) to name a few. For Indian and Mexican shirts and smocks to wear with jeans, trySerendipity (Mt. Auburn St. near Plympton St.), Bowl and Board (1063 Mass Ave.), George's Folly (30 Brattle St.), and The Lodge. Serendipity has the largest selection. J. August and Co. (1320 Mass. Ave.) has expensive good quality wear for men, and The Prep Shop (31 Church St.) will outfit anybody who can squeeze into boys' sizes, which means just about everybody.

If the tailored look is your thing, you are used to paying for it and won't sweat too much at Cambridge costs. Settebello has the best in Italian cuts, and Design Research, or DR, has its own stubborn brand of chic. Ann Taylor's is downstairs from DR; it goes in for the sort of fashion that smells of 7th Ave. Capezio's (30 Dunster St.) carries brand names like Crazy Horse, but it is not big on distinctiveness.

If you are female, buy staples like underwear, if you wear it, or pajamas, if you wear them, slips and stockings, if you are used to putting up with the hassle of bothering with them at all, at Corcoran's (14 Brattle St.) or Touraine's (38 Brattle St.) because they are the cheapest. Happy Consuming.

Books

They say that the Square sells more books than cigarettes. Now that may be a vain boast; it is no secret that many of Harvard's best and brightest make it through four years without reading any. Somebody is either compulsive or hungry for book larnin' though, because books are big business in the Square. The Coop in the Annex in back of the main building) is the largest bookstore; it stocks almost all of Harvard's textbooks. The textbooks are on the third floor, paperbacks on the second, and hardcovers on the first. The Harvard Bookstore (1248 Mass Ave.) also stocks many of the textbooks required for Harvard Courses. And the staff is nice enough to turn you off to the Coop on brotherhood principle. The used book section takes up the space of a giant store in itself--and there is a very fair give and take in the getting and the selling of them.

The Paperback Booksmith (37 a Brattle St.), open 24 hours a day, lives up to the sort of soul healing power its title implies. It has the best science fiction around, and a lot of hard-to-get books on the most far out of subjects. To top it all the staff won't bug you if you spend four hours in there one early morning making up your mind not to buy anything.

For foreign periodicals try Reading International (47 Brattle St.), but foreign language scholars should avoid this popularized medley and opt for Schoenhof's (1280 Mass Ave.) instead. It specializes in everything from books in Amharic to those in Welsh. And if they don't have what you want they will get it for you. Browsers can, be they greenhorn or fanatic, make a lifetime of it. At Grolier's (6 Plympton St.) you never know what rare antique find you may happen upon. It is the same story at the Starr Book Shop (29 Plympton St.), and the Mandrake Bookstore (8 Storey St.).

If you have read through this far, I might as well tell you that this is like a churchmouse's peephole view of Cambridge--we threw out some breadcrumbs, but the real pickings have to be tasted