I Don't Know What It Is

"I Don't Know What It Is" is a single by Canadian-American singer-songwriter Rufus Wainwright, released in a slim-line jewel case format in 2004. It is from his third studio album Want One (2003). In addition to the UK and Japanese versions of Want One, the song also appears on the bonus DVD that accompanies Want Two (Rufus Wainwright: Live at the Fillmore), All I Want (DVD), and Want, a repackaged UK double album that contains Want One and Want Two.

In All I Want, producer Marius de Vries admitted that "I Don't Know What It Is" was one of the most complex production challenges he had ever faced, with its hundreds of layers of separate orchestral, choral, and vocal parts. Between "running around" and "chugging along" "on a train going God knows where to" in a sort of aimless wander, transportation is a major theme of the song. Wainwright alludes to several locations, from precise ones such as Calais, Dover, Poland and Lower Manhattan to more abstract locales like Heaven, Hell, and Limbo. Wainwright said of the song:

References are also made to the American sitcom Three's Company; "knock on the door", "take a step that is new", and "three's company" all allude to the TV show's theme song. "Taking the Santa Fe and the Atchison, Topeka" is a reference to Judy Garland's The Harvey Girls, which itself contains an allusion to the Atchison, Topeka and Santa Fe Railway.

Wainwright performed the song on Late Show with David Letterman on October 6, 2003.

1. "I Don't Know What It Is"
2. "L'Absence" (from Hector Berlioz's Les nuits d'été, op. 7)
3. "14th Street"

Both B-sides were recorded live at The Fillmore in San Francisco in March 2004.

"I Don't Know What It Is" appeared on the UK Singles Chart for one week, entering on August 7, 2004, and reaching a peak chart position at No. 74.