Singer-songwriter and folk revivalist Pete Seeger, whose music career spanned half a century, died yesterday of natural causes at the seasoned age of 94. With little more than a 12-string guitar, a banjo, and a chorus of blue-collar blues to sing to, Seeger's music played an integral role in stitching the social fabric of mid-20th century America.

If author John Steinbeck's themes could be condensed into a melody -- from his pastoral patience and spiritualism, to his hard luck heroes and dust bowl drama -- that melody would meet its full potential in the wonderful warble of Pete Seeger's vocals. In fact, Seeger himself likened his musical career to a Steinbeck quote, having repeatedly referenced Tom Joad's emotional frustration in The Grapes of Wrath: "Wherever children are hungry and cry, wherever people ain't free, wherever men are fightin' for their rights, that's where I'm gonna be."

If our life callings were ever ordered, Seeger would have been born an activist first and a musician second. In the 1940s he helped form and play in a succession of bands, all of which were politically charged and labor-oriented. Playing first in the Almanac Singers (1940-1943) and then People's Songs (1948-1949), Seeger viewed his access to the public stage as an opportunity to affect change. His band The Almanac Singers was eventually reconstituted into The Weavers by the 1950s, gaining Seeger fame for tunes like "On Top of Old Smokey" and "Goodnight Irene."

It's hard to fathom today, after the rise of flower children and electric guitars, but to play Seeger's style of politically active folk music was a decision many deemed too risky to make. The decade following World War II was stifled by conformity, and simply challenging the status quo was grounds for alienation. You've been a naughty boy, sang The Beatles, you let your hair grown long. First, the Almanac Singers became the target of an FBI investigation for their repertoire of antiwar songs, tarnishing the band's reputation. Then in the 1950s, Seeger was called to a hearing by the House of Un-American Activities Commission, under suspicion for leaning too far left to the liking of a Red-baited nation.

Yet Seeger's empathy for the common man was marrow-deep, and his selflessness often directed his life's course, no matter the consequences. He re-popularized such classics as "We Shall Overcome" and "If I Had a Hammer." He attended Vietnam War protests and civil rights marches. He had a broad grin, open arms and an unimposing presence. All of this helped prove the purity of his intentions.

In the introduction to "Deep Blue Sea," before an audience of Bowdoin College students in 1960, Seeger muses that the best kind of folks songs are "the ones a gang of people can sing together." Even after leaving us, then, here's to hoping his music will continue to bring us closer and bridge our differences. Lord knows we need it.