Barbra Streisand, I confess, has never been one of my favorites. I do, however, admire her long-standing endorsement of Harold Arlen’s music. When she guest-starred on the songwriter’s own 1965 Columbia album, “Arlen Sings Arlen,” she described him as “the greatest composer of American music next to Gershwin.”

Arlen unquestionably is one of the very greatest of American songwriters. Along with Berlin, Kern, Porter, Gershwin, and Rodgers, he is one of the “Big Six” whose works form the core of the American canon. Yet Arlen, who was born 100 years ago on February 15, 1905, (and thus is the youngest of this imposing half dozen) had a career like no other.

He began his career as a specialist in material for African-American performers, serving as composer-in-residence at Harlem’s world-famous Cotton Club. Yet some of his most famous pieces are written in an overtly operatic style. He spent the largest part of his career as a salaried songwriter in Hollywood, writing scores for dozens of films that are, essentially, only remembered for his songs. But he never created a Broadway show that was considered a classic (although his score to “The Wizard of Oz” most assuredly is). Yet even if his shows aren’t revived, his songs are known to nearly everyone.

Arlen achieved his initial fame during the Great Depression, with his Cotton Club songs: “Ill Wind,” “I Gotta Right To Sing the Blues,” “Between the Devil and the Deep Blue Sea,” “I’ve Got the World on a String,” and others, all with lyrics by Ted Koehler. These are so much a part of the black jazz experience that they are often presumed to be the work of an uptown composer like Duke Ellington or Fats Waller.

Later, working with the more poetically inclined librettist Yip Harburg, Arlen came up with an amazingly different body of work: “Last Night When We Were Young” boasts a soaringly Puccini-esque melody. “Over the Rainbow” opens with an octave leap that was so daring in its day it intimidated the producers into trying to have the song scissored from “The Wizard of Oz.” And finally, with Johnny Mercer, Arlen created a third body of astounding work, stridently jazzy songs like “Blues in the Night,” “That Old Black Magic,” “My Shining Hour,” and “Come Rain or Come Shine” that have become authentic American folk music.

The composer’s son, Sam Arlen, a saxophonist and bandleader in his own right, makes a very pertinent point about his father’s upbringing. Harold Arlen’s father, Samuel Arluck, was a cantor in Arlen’s native Buffalo. Equally important, he was a scholar with a wide range of interests.

“Cantor Arluck was, of course, devoted to the Jewish faith, but he was interested in all kinds of knowledge and beliefs,” said Mr. Arlen, who has just released a new CD of his father’s music, “Arlen Plays Arlen” (JoSam Records 0215). “He saw life as a series of discourses between different philosophies and would often discuss religion with members of other faiths.”

The Arluck household was what would today be described as cross-cultural; there was a free exchange of religious ideas, and musical ones, too. Young Hyman Arluck caught the musical bug at a very early age and began studying the piano. It was his parents’ wish that he should become a cantor like his father, or if not that a classical pianist, composer, or conductor. But there were other influences at work.

“Cantor Arluck lived in a two-family house in Buffalo, and he rented out the other half of the building to a black family – needless to say, that was very unusual at the turn of the century, even in the North,” Mr. Arlen said. The lives of the two families became closely intertwined: The children grew up together, and they all celebrated each other’s holidays.

Thus, Hyman was exposed to emerging strains of Afro-American music – which at that time would have meant ragtime, if not yet jazz or blues – long before any of his Broadway contemporaries. Jazz would be an ineffable part of who he was and what he wrote, much as cantorial music and other kinds of traditional Jewish music were. “The blues and jazz were not something that he had to learn or study,” Sam Arlen said. “This was a music that just naturally emanated from him.”

In this, the comparison with Gershwin is especially apt: Arlen and Gershwin were the only members of the Big Six who were not only sympathetic to jazz but actually excited about it. Where Richard Rodgers would have balked if you put one of his tunes into swing time, Arlen, as friend Tony Bennett put it, “was in favor of anything you could do with his songs that would please the public.” Likewise, Gershwin was flattered when, even in his lifetime, jazzmen found zillions of uses for his chord sequences (notably “I Got Rhythm”).

Arlen’s melodies didn’t even need to be rewritten; the way he wrote them they sounded jazzy enough. When Louis Armstrong sings “I’ve Got the World on a String” or “I gotta Right To Sing the Blues,” or Ray Charles does “Come Rain or Come Shine,” it doesn’t sound like a black performer jazzing up a show tune. It sounds like a jazz singer doing material from his own tradition.

It can’t be a coincidence that Gershwin and Arlen were also the only two of the Big Six who had any talent to speak of as instrumentalists. Both supported themselves as professional pianists before their Ascap royalties began coming in. Gershwin came up through the world of songwriters and song publishers; Arlen entered the music industry by means of the dance bands that at the time were very close, often indistinguishable, from hot jazz.

That’s where the similarities end, however, for their ambitions were very different. For Gershwin, Broadway musicals were his bread and butter, but the prize he had his eyes on was academic respect, which he sought to achieve by writing rhapsodies, ballets, and an opera. He created some great music in the process, even if he failed to knock Mozart off his pedestal.

Arlen, like Johnny Mercer and Hoagy Carmichael, valued the respect he earned in the jazz and pop community, but for him the goal was Broadway. Nothing could top the respect a composer earned by writing a great musical. In America, that was the top of the food chain. Arlen, like Carmichael and Mercer, spent most of his career as a writer of songs for Hollywood films, and virtually every time he wrote for the New York stage, it was almost always for an African-American production of some sort,, from the Cotton Club through the film version of “Cabin in the Sky,” “St. Louis Woman,” “House of Flowers,” “Jamaica,” and “Free and Easy.”

Indeed, there are only a handful of Arlen shows with all-white casts: “Life Begins at 8:40,” “Hooray for What,” and “Saratoga.” His biggest hit was “Bloomer Girl,” one of many slices of Americana that caught on in the post-“Oklahoma!” atmosphere of World War II. But even here, the subplot, about a runaway slave who yearns to be free, is more memorable than the main plot, regarding a 19th-century liberated woman who trumpets her rebellion against patriarchal oppression by exhibiting her underclothes.

“Stormy Weather” is Arlen’s “Summertime” – a song so rooted in African-American vernacular music that it is often taken for an authentic blues or traditional song. Originally written with Cab Calloway’s shouting style in mind, the song was introduced by Ethel Waters – in fact, she only agreed to appear at the Cotton Club on the condition that she would get to sing it.

It’s hard to think of another song so steeped in blues performance traditions. “Stormy Weather” has a rich, bluesy melody (he opens on a blue note), which harmonizes adventurously with a brilliant pattern of major, minor, and diminished chords. But Arlen’s most striking innovation is a series of repeats at the end of most of the song’s eight-bar segments, in which he has written in variations of the kind that Waters or Louis Armstrong might have added as an improvisation.

“Stormy Weather” was Arlen’s first really big hit, one of the most popular songs of the 1930s, and indeed of all time. It perfectly captured the mood of the Depression with a brilliantly conceived melody in which each man could be his own Armstrong. In the years since, Arlen’s music has become such an essential part of our culture that it’s impossible to imagine the landscape of American music without it.

Tributes to Harold Arlen, Live & on Disc

Arlen’s actual birthday is February 15, but by that time no fewer than two major live-performance events will have occurred to kick off the centennial.

Tonight the Harold Arlen Centennial Celebration kicks off at the Blue Note, where it will continue at 8 and 9:30 p.m. until January 30. Performers include Dena DeRose, Ann Hampton Callaway, Andy Bey, Eric Reed, Kenny Washington, Peter Washington, Harry Allen, and Jeremy Pelt. (131 W. 3rd Street, between Sixth Avenue and MacDougal Street, 212-475-8592).

Then on February 14 at 8 p.m. Carnegie Hall will host Let’s Fall in Love: Harold Arlen: A Centennial Celebration. The lineup there will include Eric Comstock, Loston Harris, Ann Hampton Callaway (yes, her again), Barbara Fasano, John Pizzarelli, Jessica Molaskey, Tedd Firth, Steve LaSpina, Steve Johns, Maureen McGovern, Faith Prince, and (whew) Tom Wopat (57th Street at Seventh Avenue, 212-247-7800).

In addition, there are at least four commemorative CD collections, though doubtless there will be more before 2005 is through.

Get Happy: The Harold Arlen Centennial Collection Verve-Universal Music (B0003977-02) has the greatest lineup of superstar jazz vocalists, and this anthology compiled by Sam Arlen contains all the most familiar songs and the biggest names; Ella Fitzgerald, Sarah Vaughan, Joe Williams, and Louis Armstrong. My favorite is Abbey Lincoln’s lopsided reading of “If I Only Had a Brain.”

Harold Arlen Centennial Celebration (Concord Jazz CCD2-2270-2), an ambitious two-disc collection, is the first to result from the recent Fantasy-Concord merger, and combines singers like Rosemary Clooney and Mel Torme with instrumentalists like Bill Evans, Roy Eldridge, and Oscar Peterson.

Shorty Rogers: The Wizard of Oz and Other Harold Arlen Songs (DRG CD 8482) is one of a brilliant series of pop jazz albums created by flugelhornist and arranger Shorty Rogers in the 1950s. His 1959 settings of the “Wizard” score are wonderfully whimsical as well as swinging.

Arlen Plays Arlen (JoSam Records 0215) Arlen’s only child Sam is a talented saxophonist and bandleader, and he produced this auspicious collection of new arrangements of both classic and lesser-known songs by his father. There’s nothing to compete, however, with the voice of Harold Arlen himself singing “It’s a New World,” which he and Ira Gershwin wrote for Judy Garland. Arlen’s vocal and piano track, recorded for The Music of Harold Arlen: The 1955 Walden Sessions (Harbinger Records), has been outfitted with a new, full orchestration – a whole new world indeed.