A second great American is being remembered on the 100th anniversary of his birth this year, one who perhaps made a far more positive and constructive contribution. March 26 will mark 100 years since the birth of playwright Tennessee Williams, a man who, until his passing in February 1983, was a prolific writer of painfully authentic works that called attention to the often less-than-ideal conditions of humanity.

The Williams Centennial is being celebrated by a spate of some of his later, less well-known and appreciated plays in Manhattan, and by a three-day festival hosted by the Georgetown University’s Theater and Performance Arts Studies Department, beginning with a talk by Edward Albee on March 24 and running through March 27.

Williams is best known for his towering achievements beginning with his breakthrough “The Glass Menagerie” in 1944, and followed by Pulitzer Prize-winning efforts such as “A Streetcar Named Desire” and “Cat on a Hot Tin Roof.”

Many of his works from the 1940s and 1950s were also turned into film hits, including, in addition to the above, “The Rose Tattoo,” “The Night of the Iguana,” “Sweet Bird of Youth” and “Suddenly Last Summer.”

His themes were always gritty and uncompromising, and drew attention to a number of important social issues, such as the demeaning treatment of women and minorities, especially in the South, and a recurring preoccupation with the savage medical practice of frontal lobe lobotomies, one of which had been performed on Williams’ own sister.

His works stood as towering achievements for a progressive age, coming on the heels of America’s defeat of fascism in World War II and a new optimism about the extension of the United Nations’ “Declaration of the Universal Rights of Man” to bring equality, democracy and progress to the four corners of the globe.

Williams’ influence was felt not only on Broadway, but on college campuses across the nation, where his plays were studied and performed, and helped to spark a new sensibility among a post-war generation eager to right the persisting wrongs of racism and segregation in the South and the brutish policies of what President Eisenhower identified as “the military-industrial complex.”

But it became the popular view that Williams underwent a sharp decline in his work in the early 1960s, in part attributed to the death of his longtime companion, Frank Merlo. Following his last critically-acclaimed hit, “The Night of the Iguana,” he produced a string of plays that failed to impress critics or hold onto audiences.

The first product of that period was “The Milk Train Doesn’t Stop Here Anymore” introduced in 1962, which is now enjoying a rare revival on stage in Manhattan starring Olympia Dukakis.

In an article entitled “New Light, Long After His Sun Set” in last Sunday’s New York Times, critic Charles Isherwood challenged “the simplistic view that Williams’ later work reveals a stark and irreversible decline in his talent.”

He credits “the beauty Williams found in the miracle of human endurance,” noting that Williams referred to artists as “desperate searchers after whatever can be found of truth and beauty, even when the two may be poles apart.”

In his later plays, Isherwood commented, Williams, who he calls “the most compassionate of playwrights,” “simply digs more deeply into this dark terrain, writing with new frankness about people holding onto respectability, dignity, sanity by their bleeding fingertips. Loneliness, his great theme, is etched more starkly.”

In addition to “Milk Train,” other later works, “Small Craft Warnings” (1972) and “Vieux Carre” (1978) are being prepared for productions in New York this spring. A highly adept production of “Small Craft Warnings” was put on by the Washington Shakespeare Company in 2009.

Perhaps the real explanation for the “decline” in Williams’ work in the 1960s was that the nation’s mood was shifting away from his gritty socially-progressive views (he voted for Norman Thomas for president in 1932) toward a post-modern, valueless form of “realism” that contributed to the nation’s withdrawal from its civil rights and anti-war passions of the 1960s toward its subsequent decades of selfishness, consumerism and hedonism.