VIDEO: Stephen Schwartz & More Appear in Trailer for New Documentary THE SOUND OF OZ

Everyone knows the songs from The Wizard of Oz; in fact, Over the Rainbow is often cited as the greatest movie hit of all time. Few, however, know the names of the men who wrote Rainbow and the rest of the classic Oz score.

The remedy for their anonymity now is in the hands of Aaron Harburg -- great-grandson of The Wizard of Oz lyricist E.Y. "Yip" Harburg -- who has begun production on The Sound of Oz. The feature-length documentary honors both his great-grandfather and Oz composer Harold Arlen.

View The Sound of Oz trailer below!

The twenty-eight year old Harburg already has assembled a teaser trailer that heralds the two men and their Oz work. It also discusses the history and impact of the Harburg lyrics and Arlen melodies. "So many lives have been changed by the songs from The Wizard of Oz," he explains. "From If I Only Had a Brain to We're Off to See the Wizard to Ding-Dong! The Witch is Dead, there are countless untold stories of people who have found inspiration and joy in my great-grandfather's words. Yet few people know who he is. I hope to use the power of film to introduce the Oz songwriters -- and their creative process -- to the world."

While the making of The Wizard of Oz has been documented in numerous books and on home video, the specific story behind the film's songs has yet to be told. The Sound of Oz will detail the magical (and sometimes-combative) relationship Harburg's great-grandfather shared with composer Arlen. "They were very dif-ferent personalities, almost opposites," notes Aaron. "My great-grandfather was sanguine and chipper, while Mr. Arlen was a classic melancholic."

"Yet the first time my great-grandfather heard the melody for Over the Rainbow, he hated it," admits Harburg. "It wasn't until Ira Gershwin intervened and sug-gested Mr. Arlen play it differently − less symphonically − that Yip began to see how it could work."

Over the Rainbow won the Academy Award for "Best Original Song" just seven-ty-five years ago. Since then, it's been honored as the #1 Film Song of All Time by The American Film Institute and #1 Song of the Twentieth Century by The Na-tional Endowment for the Arts and The Recording Industry Association of Ameri-ca. The irony of this - to be explained in The Sound of Oz - is that the number was nearly dropped from Oz, not once, but several times.

"Each brilliant musical moment in The Wizard of Oz has a behind-the-scenes story of Hollywood politics, teamwork and negotiation," offers the film's director, Ryan Jay. "We plan to finally share those stories."

The Sound of Oz also will explore the genius struck between composer and lyri-cist, as divulged in interviews with descendants of the original cast and crew, in-cluding Jane Lahr (daughter of "Cowardly Lion" Bert Lahr). The documentary will contain additional insights and comments from filmmakers of other Oz movies; Oz historians (including Emmy Award-winning producer/writer and Grammy Award-nominated journalist John Fricke); and several contemporary artists who sing, play, or are influenced by the Oz score to this day.

"The Wizard of Oz wouldn't have remained as iconic as it has without the songs," says Stephen Schwartz, composer/lyricist of the multi-billion dollar Broad-way sensation, Wicked, who sat down with Harburg and Jay last autumn for an on-camera interview. For the first time on record, Schwartz reveals - and plays -- the strategically-hidden melody fragments from the songs of The Wizard of Oz that he incorporated in his score for Wicked.

Given his unique family background, it's likely that only Aaron could gather such a cast of participants. The Sound of Oz grew out of his passion, and it was his initial hope that the project would carry on his family legacy, providing long over-due recognition for lyricist Harburg and composer Arlen. But it has grown into more:

"I see now how important their story is to fans of The Wizard of Oz. From very humble beginnings, my great-grandfather partnered with Mr. Arlen, and together they crafted words and melodies that launched the golden era of movie musicals. Their story will inspire everyone to pursue their dreams, to never give up...and to always keep chasing the rainbow."

For more on The Sound of Oz visit www.thesoundofozmovie.com.