"You Know My Name (Look up the Number)" is a song by The Beatles, written by John Lennon and Paul McCartney, and originally released as the B-side of the single "Let It Be" on 6 March 1970. Although first issued with their penultimate single, it was recorded in five separate sessions beginning with four in May and June of 1967, and one in 1969.

Earlier in 1967 Frank Zappa released the song "America Drinks and Goes Home" on the Mothers of Invention album Absolutely Free where he also combined a silly tune with nightclub sound effects to parody his formative years in the early 1960s playing with drunken bar bands. Similar tunes were also recorded by The Rolling Stones, "On With The Show" (1967) and Jimi Hendrix, "My Friend" (1968).

The song is a music hall comedy number and is perhaps the silliest song in the Beatles' catalogue. Lennon came up with the lyric and title after seeing a phone book. He said:

McCartney once told Beatle recording analyst Mark Lewisohn, "[People] are only just discovering things like 'You Know My Name (Look Up The Number)'—probably my favourite Beatles' track!" He went on to explain:

The song features a saxophone solo played by the Rolling Stones' Brian Jones.

The recording includes a reference to Dennis O'Dell, associate producer on the A Hard Day's Night film, . Partway through the song, Lennon introduces McCartney as lounge singer "Dennis O’Bell," one consonant away from the name of the film producer Lennon had worked with not only on Hard Day's Night but also How I Won the War. The reference prompted numerous telephone calls to O'Dell's home by fans who told him, "We have your name and now we've got your number," as well as personal visits by fans wanting to live with him.

"You Know My Name," performed by Chris Cornell, is the theme song to the 2006 James Bond film, Casino Royale. Cornell wrote it jointly with David Arnold, the soundtrack's composer. The track was leaked onto the Internet on 20 September 2006. It is the first Bond theme to be sung by a male vocalist since 1987's The Living Daylights (only the fifth overall) and is the first Bond theme since 1965's Thunderball to be sung by a male soloist. It is also the first since "All Time High" (1983) — the theme to the film Octopussy — not to feature its film's title in the lyrics (Dr. No and On Her Majesty's Secret Service featured instrumental songs in their openings.)

Although the song does not feature its film's title in the lyrics, references are made to casino gambling and other themes from the film. For example: "Try to hide your hand" (of cards), "I've seen this diamond cut through harder men" (with the image of the card suit on-screen), and "a spin of the wheel" (in reference to roulette). References to other themes include "When the storm arrives, would you be seen with me?" (a question of loyalty), "The odds will betray you," and "Forget how to feel" (an allusion to the general dispassion of Bond). In the film itself, Mathis makes a reference to the line "The coldest blood runs through my veins," when he asks Bond, "Has our girl melted your cold heart yet?"

Cornell cites Paul McCartney's theme for Live and Let Die and Tom Jones's theme for Thunderball as his inspirations for writing this theme.

As with all Bond films the theme plays against a synchronized title sequence. This sequence, like those of previous Bond films starting with 1995's GoldenEye, is designed by Daniel Kleinman; however, it eschews the nude female silhouettes sprinkled liberally throughout the title sequences of both Kleinman and his predecessor, Maurice Binder. Instead, card game and mathematical symbolism and stylized animated fight sequences (e.g., henchman burst into heart symbols after being attacked by Bond, club symbols changing into a picture of the Mandelbrot set) serve as the backdrop.

The song is the first Bond theme not to be included on its film's soundtrack album. A second version with more orchestration was used for the music video. A third orchestrated version was used for the movie. Yet another version with very little orchestration was present on the MySpace page for the movie itself. The video for the single premiered on MTV's Making the Video on October 31 2006.

The first version of the song, the grittier one which was leaked and not used in the movie, was made available for download on iTunes Store on November 13 2006. This version debuted on the UK Single Download Chart at number 20 on November 22 2006. It was released as a stand-alone single on December 14 2006. The single features a new acoustic version of the Soundgarden song "Black Hole Sun" as a B-side. The German, Dutch and Australian versions of the single offer a second version of "You Know My Name" (called the Pop Mix) as a B-side. . This version is the one used for the song's music video, and is available on Chris Cornell's solo album, Carry On.

In 2007 Chris Cornell won the Satellite Award for "You Know My Name" and garnered a first-round nomination in the "Best Original Song" category for the 2006 Academy Awards (the song did not qualify for the final list of nominees). It was also nominated for the Best Song Written For Motion Picture, Television Or Other Visual Media Grammy Award in 2008.