On Saturday, March 19, the Symphony Space will present the 35th in its series of Wall to Wall marathons. This year, the event is a 12-hour tribute to the work of legendary composer/lyricist Stephen Sondheim - presented three days before his 75th birthday. Promising to generate the longest queue in town, the event is free to the public, with Symphony Space members (in good standing as of 5:00pm March 18) receiving priority seating. Presentations are organized into 3-hour segments, with the crowning segment beginning at 8:00pm as Paul Gemignani conducts The American Theatre Orchestra to accompany a star-studded lineup of performers presenting highlights from the Sondheim oeuvre - all topped off by the presentation of a birthday cake and a group sing of "Happy Birthday" (in the key of F) to the honoree himself. [Can't be there? See the end of this article for alternative ways to hear all or part of the event.]

One can only imagine the amount of planning and organization necessary for an event of such magnitude. By day's end, 163 singers will have sung, accompanied by 210 chorus members and musicians, supported by 127 Symphony Space staff members and crew. It all started at a birthday party for a mutual friend of Symphony Space Artistic Director Isaiah Sheffer and Stephen Sondheim. Though not previously acquainted, Sheffer took the opportunity to ask Sondheim how we would feel about a March 2005 Wall to Wall Sondheim marathon. Sondheim answered that he'd be honored, and the plans begin.

For a legendary artist who has been honored by the Kennedy Center and won many awards, including six Tonys (nominated 15 times), what more could be done? According to Sheffer, you give the Wall to Wall fans what they want, "a leisurely but highly crafted exploration of Sondheim's work ... not the fanciest or glitziest of birthday celebrations, but ... the longest, deepest and broadest of tributes." Offer the popular Sondheim songs and the obscure, including some cut and never-presented pieces for the diehard Sondheim follower. And invite a lot of stars of musical theatre; as performers were approached, a common reply from a number of the very busy musical theatre veterans, including Paul Gemignani and Angela Lansbury, was, "For Stephen Sondheim, I've got to be there."

Performers and speakers include many original and revival cast members from Sondheim shows on Broadway (Barbara Barrie, Kate Burton, John Dossett, Greg Edelman, Harvey Evans, B.D. Wong, Elaine Stritch, Angela Lansbury, George Hearn, Donna Murphy, Lonny Price, Patrick Cassidy, Marc Kudisch, Liz Callaway among others), fellow composers and lyricists (Sheldon Harnick, Andrew Lippa, Jason Robert Brown, David Shire, Richard Maltby, Jr.), and a score of other talented performers (including Emily Skinner, Andrea Burns, Michael Arden, Phyllis Newman, Barbara Cook, Lauren Kennedy, Alan Campbell, Debbie Gravitte). Musical arrangements are provided by Andrew Lippa, Nora York, Georgia Stitt, Don Sebesky, Jason Robert Brown and Jed Distler.

Kicking off the day will be a Mayoral proclamation of "Wall to Wall Stephen Sondheim Day," followed by the presentation of an excerpt from Musical Theatre International's "junior edition" of Into the Woods, with 15 young singers on stage and 108 more in the audience performing "Children Will Listen." Special pairings and groupings will add to the festivities throughout the day: in "Waiting for the Girls Upstairs" from Follies, original Broadway cast members who played the younger versions of the characters now perform the older parts (Harvey Evans, Kurt Peterson, Marti Rolph); and Angela Lansbury and George Hearn reunite on "A Little Priest" from Sweeney Todd. Spoken tribute will be offered by Jonathan Schwartz, who will broadcast his radio show live, a reading from Everything Was Possible by author Ted Chapin, and a discussion of "Sondheim and the American Culture" moderated by Frank Rich.

As only four of the 35 Wall to Wall events have been tributes to living composers, Mr. Sondheim's participation is invaluable. "Not that he's creating the day or making decisions," says Sheffer, "but he's made suggestions and told us about rarities from early on in his career," even from Sondheim's college days. One contribution, in a segment called "Waltz King of Our Day " (in which the composer's fondness for three-quarter time is illustrated), is a one-minute piece written by Leonard Bernstein for Sondheim on the occasion of an earlier birthday (the piece will be played by Beata Moon). Sondheim will be in attendance throughout the day, appearing as part of the program during an interview hosted by Jonathan Schwartz and in the discussion moderated by Frank Rich, accompanied by Melissa Bernardo, Andrew Lippa and Joss Whedon.

Rehearsals have taken place at the Symphony Space since Monday, and a nine-hour orchestra rehearsal is set for today. But individuals have been practicing their own contributions for some time, in homes and studios. A large crowd is expected, especially with current weather predictions of a sunny day, but there are hopes that attendees will stop in, stay awhile, and then make room for more to file in and enjoy the performances. Audio speakers will be in use outside the theater, and the concert will be played there for those waiting in line to enjoy.

The complete 12-hour event will be presented on XM Satellite Radio, on channels 28 and 200. Bookending the broadcast will be all Sondheim selections from midnight tonight through the beginning of Wall to Wall, and again after Wall to Wall through 3:00am on Sunday. Visit www.xmradio.com for more information, including a free 3-day trial offer for their Internet broadcast service. Jonathan Schwartz' "Saturday Show" is part of the program and will be simulcast on WNYC 93.9 FM and online. More information is available at www.wnyc.org. Talks are underway with NPR to produce two or three one-hour specials and there are hopes to interest a recording company in making a CD commemoration.

The schedule for Wall to Wall Stephen Sondheim can be found at www.symphonyspace.org. Doors open at 10:30am (expect the line to begin much earlier) at the Peter Jay Sharp Theatre, 2537 Broadway at 95th Street. To become a Symphony Space member, call 212.864.1414 ext. 229. As a free event, the Symphony Space invites underwriting support. In recognition of this support, they will make available a very limited number of reserved seats per 3 hour segment for donors of $250 or more. For information call 212.864.1414 x232 or email sharmin.mahmud@symphonyspace.org. The Wall to Wall Hotline number is 212.864.1414 ext. 403.

Wall to Wall Stephen Sondheim is created and produced by Isaiah Sheffer, Maren Berthelsen and Joel Fram.

-- Ann Miner, with assistance from staff members Rob Lester, Alan Gomberg and Bob Rendell

The Light in the Piazza begins previews March 17, and opens on April 18, at the Vivian Beaumont Theatre at Lincoln Center. For ticket and performance information, visit Tickets online and current Performance Schedule: Telecharge