When Lincoln Center launched the American Songbook series in 1998, audiences might have expected the usual suspects: cabaret goddesses crooning tunes from such familiar names as the Gershwins, Duke Ellington, Rodgers and Hart, and their ilk. But Lincoln Center's American Songbook defies expectation. Increasingly over the last few years, American Songbook has embraced a broad sweep of the country's rich musical legacy. American Songbook can give its regards to Broadway with the best of them, but the series does more than that: it encourages established artists to venture into unexpected repertoire; it presents the foremost interpreters of jazz, popular sounds, country, bluegrass, and rock; and it produces original music-theater works that have yet to be categorized.

American Songbook reveals the connections between the classics of American songwriting and the hottest composers and performers working today, so that a single season can venture from Jule Styne to hot young singer-songwriters Sufian Stevens and Duncan Sheik. Programs have been devoted to everyone from Irving Berlin and pop and soul elder statesman Stevie Wonder to indie hipster Nellie McKay. Performers are drawn from across the musical and cultural spectrum. In one of last season's hottest tickets, the chart-topping rockers of Fountains of Wayne played a rare acoustic set for American Songbook. The group appears in arenas, rock clubs, and on Late Night with Conan O'Brien, so the chance to hear the guys behind the 2002 MTV hit "Stacey's Mom" in the intimate Allen Room guaranteed a box office feeding frenzy. That season's other hottest ticket was an electrifying concert by Broadway legend Elaine Stritch. American music doesn't get much more eclectic than that.

The current American Songbook season embraces a show biz giant (Betty Buckley, with two shows on February 10, due to popular demand), a veteran jazz-pop singer (Michael Franks, January 20), a rising jazz-pop chanteuse (Jane Monheit, February 24), a so-cool-she's-hot singer and songwriter (Neko Case, February 23), and two Oscar-winning lyricists (Alan and Marilyn Bergman, February 2). Rapper and actor Mos Def (January 17) will make his American Songbook debut branching out from hip hop with a jazz-influenced spin on works by artists like Gil Scott-Heron and Miles Davis. He'll be performing as bandleader and singer with his own Mos Def Big Band. And then there's Teutonic temptress Ute Lemper (February 21), bringing her smoldering sensuality to the songs of Van Morrison, Joni Mitchell, and Kurt Weill, and the wildly talented bluegrass family known as The Cherryholmes (February 7). And many more.

Given the multiple attractions of the season's 18-event lineup, once the American Songbook kicks into gear on January 17 with Mos Def, it might not be a bad idea to set up a cot in the lobby of The Allen Room at Jazz at Lincoln Center and move in for the duration.

Who shapes the series? Jon Nakagawa, Lincoln Center's Producer for Contemporary Programming, composes each Songbook season in collaboration with Vice President for Programming Jane S. Moss and Associate Producer Charles Cermele. Moss and Nakagawa, composer Ricky Ian Gordon, and director Doug Varone were all given a special 2005 Obie Award for Songbook's world-premiere production of Orpheus and Euridyce. And last March, Songbook won a special award from Back Stage, the weekly newspaper that chronicles New York's theater scene, "for perpetuating the tradition of American songwriting."

Ask Nakagawa to identify the quintessential American Songbook performer, and he replies without hesitation, "Audra McDonald. Audra and her concerts last October personified what we're trying to do with this series as a link between the history of American songwriting and today's songwriters, whether they are new musical-theater writers like Jason Robert Brown or contemporary songwriters like Laura Nyro, John Mayer, and Nellie McKay. Audra connects it all. She personifies — and I don't use that word lightly — what we're trying to with American Songbook."

Programming a season typically takes a year, says Nakagawa. "Because American Songbook is so eclectic and we deal with many different worlds, putting a season together can take quite a while. Some artists need to book a year or more in advance; some can't book a month in advance. Many events and artists require cultivation. Alan and Marilyn Bergman, for example, had done a tribute to composer Cy Coleman in Los Angeles. We approached them about bringing that to Songbook, but they weren't available. So we stayed in touch with them and realized that their 50th anniversary as a songwriting team would make a perfect show for American Songbook." Singers Jessica Molaskey and Melissa Errico, among others, will join the Bergmans to perform songs from the composers' Oscar-winning songbook, including "The Windmills of Your Mind," "The Way We Were," and "What Are You Doing the Rest of Your Life?"

While lyricists such as the Bergmans stick to the kind of music-making they virtually define, other artists spread their wings for this series. "Mos Def is a great fit for us — he's a contemporary performer known for working in his own genre who is doing something different, for a different audience, at American Songbook," says Nakagawa. "He's someone who could fill Radio City Music Hall playing rap, but this is a chance for him to try something new.

"Pretty much across the board, we try to give artists a free hand," Nakagawa continues. "We talk about repertory and help them with whatever they need, but artistically we look to them for guidance on what they want to do. Betty Buckley is another example of a performer working outside of her genre. She may do Broadway songs on February 10, but she will be singing with a jazz quintet. Fred Hersh is known as a jazz pianist, but he's an accomplished composer in his own right, and his Songbook concert will feature his original compositions, performed by two jazz and two Broadway vocalists. The immensely gifted musical-theater composer Jason Robert Brown will present an evening of his own compositions, while singer Howard Fishman will interpret Bob Dylan and The Band's Basement Tapes, which have achieved cult status. And some performers are not quite what you'd expect for a series in New York, such as Calexico, a country-rock group with a very southwestern feel."

Anything particularly unexpected for the Songbook season? "The real surprise for me," Nakagawa admits, "are the Cherryholmes. They are bluegrass artists, and they are great. Bluegrass is underrepresented in New York City, and yet it has a real place in American Songbook. The purity of the sound that the Cherryholmes have is so beautiful that when I heard their album I thought, we have to have them."

Robert Sandla writes frequently about the arts.

American Songbook is a presentation of Lincoln Center for the Performing Arts. Major support is provided by Richard L. Fisher and Amy & Joseph Perella. For tickets, call CenterCharge at 212.721.6500, or visit the Lincoln Center Web site at www.lincolncenter.org.