HARVARD may have long since forgotten the Class of '21, but the Class of '21-or at least part of it-has not forgotten Harvard. These men are returning this week for a fiftieth reunion in Cambridge at a time when the future of America's oldest college is as uncertain and unsure as at any time in its history. They are revisiting a Harvard that has few recognizable similarities to the institution that awarded them diplomas half a century ago. But they are coming back-and that, well, must say something.

There were about 650 members of the Class of '21, about 360 of whom are still alive today. Twenty members of the class are "lost"; of the deceased, about 75 have died in the past five years. Still, at least 125 old Harvard men are spry enough to make the trip to their old school this commencement week and arrive they did at Dunster House, their reunion headquarters. Dunster House, of course, did not exist when these men were undergraduates.

As college boys, these were the people Scott Fitzgerald chronicled in This Side of Paradise, a first novel which caused a sensation during '21's junior year. They graduated into a world of raccoon coats and Warren Harding, crazy prosperity followed by a dizzying bust. During the final weeks of their spring reading period, Sacco and Vanzetti endured their first trial. In 1921, Lenin announced his New Economic Policy, Ezra Pound's first four cantos were published, and Eugene O'Neill's Anna Christie hit the boards. Radio was catching on.

But all that's water under the bridge, isn't it? The Class of '21 survived and, like all Harvard classes, mine ('71) included, went on to provide the world with investment bankers, lawyers, corporation directors and trustees, doctors, scientists, teachers, salesmen. Harvard '21 also gave the world some celebrities and, although it's not nice to talk about such things, some failures.

Interestingly enough, most of the famous names of '21 are in one field: journalism. John Cowles, king of the publishing family that recently gutted one of America's best magazines ( Harper's ), is in the class. So is Roy Larsen, Time-Life kingpin, who, in his autobiographical note in the class's reunion report, offers to send classmates copies of the recent Time Inc., The Intimate History of a Publishing Empire "with [his] compliments." And there is also none other than Lawrence Spivak, the tough-minded moderator of the long-run Meet the Press.

George Kennedy '21 is a journalist I'm particularly familiar with, as he wrote the "Rambler" column, a mainstay feature of one of my hometown papers (The Washington Evening Star ), for several decades. Harold Guinzburg, who died in 1961, is the publisher who founded the still flourishing Viking Press as well as the Literary Guild of America.

NOT THAT this class failed to come up with the stuff in areas outside the publishing world. Jack Straus (of the Macy's family) was here fifty years ago and is still around to lament that his "greatest frustration in life [has been his] lack of athletic prowess." (Oh well. He survived.) A classmate of Straus's was Paul Tishman, and Mr. Tishman is an interesting case. In the class report, the Secretary notes that he has heard nothing about Mr. T since the 30th reunion, at which time "he wrote that he was in the contracting and building business." Talk about euphemisms! Mr. Tishman has built some of the most financially lucrative, not to mention ugliest, skyscrapers in New York. (Tishman buildings can often be identified by their pimples.)

Members of Harvard '21 were generally too young for World War I and too old for World War II (only five classmates lost their lives in combat), so perhaps it's not surprising that there are few politicians among its ranks. Still there is Powers Hapgood (d., 1949), who completed Harvard in three years so he could spend his senior year working in iron and coal mines, railroad yards and Chicago slaughter houses. Hapgood went on to become a leader of the United Mine Workers, a defeated Socialist candidate for Governor of Indiana, a major organizer of the CIO and an early member of the NAACP.

One member of the class was assassinated -Yii Loo Tang, who met his demise while working for the Nationalist Chinese Minister of Finance in 1931.

Others entered show business. Harvard '21 gave us Royal Beal, the character who died recently. There was also Robert Lord, who wrote Tom Mix westerns and won an Oscar for best screenplay (in 1932 for One Way Passage, a Tay Garnett picture) and worked with L. B. Mayer, Harry Cohn, Jack Warner and Humphrey Bogart. Another member of the class toured in a road company of Blossom Time.

MOST OF THESE Harvard men, though, led quiet lives. Many of them are enjoying retirement in Florida or the upper reaches of New England now, and, in the mini-autobiographies they sent to James Lowell, their class Secretary, they often reveal the kind of good humor and intelligence that never goes out of style.

George Cutler, for instance, described his life as "A Complete Flop." Joseph Bransten wrote that his "business career has been one of complete nepotism." I would particularly like to meet the class's most flamboyant live wire, Serge Daniloff, who wrote:

Occupation: None.

Sports: Stopped sports car racing in 1964 and riding to hounds in 1969. Riding, however, is still my favorite sport (France). Next: swimming (Mediterranean).

Intellectual pursuits: Reading is my violent passion. I read everything and remember nothing. Moving to larger quarters to accommodate my ever-growing library. I am very much interested in modern painting (figurative and abstract) and in chamber music (except dedacophoni)....