& is an extended play by Japanese recording artist and songwriter Ayumi Hamasaki. It was released on July 9, 2003, by record label Avex Trax. Hamasaki's fourth extended play, & consists of four recordings; "Ourselves", "Greatful Days", "Hanabi: Episode II", and "Theme of A-Nation 03", with three additional instrumentals of the first three tracks. It was released in two different formats; a stand-alone CD, and a digital EP. The artwork for the EP depicts Hamasaki posing in front of a cloudy backdrop, with the title of the work superimposed over her hair. & contains predominantly J-pop and dance music.

Hamasaki contributed by writing the lyrics to all the tracks, while Japanese production and manager Max Matsuura served as the EP's main producer. & received favourable reviews from music critics who commended the EP's production and commercial appeal. & reached number one on the Oricon Singles Chart, and was certified double platinum by the Recording Industry Association of Japan (RIAJ) for shipments of 500,000 units. "Ourselves", "Greatful Days", "Hanabi: Episode II", and "Theme of A-Nation 03" served as promotional singles, while all but the latter track receiving music videos respectively. & was awarded the Japan Record Award at the 46th Japan Record Awards for Best Pop/Rock Album.

Ayumi Hamasaki announced that she would release a new extended play, marketed as a single, entitled &. It consists of four recordings – "Ourselves", "Greatful Days", "Hanabi: Episode II", and "Theme of A-Nation 03" – with additional instrumental versions of the first three tracks.^[1] & was released on July 9, 2003, as the first single from Hamasaki's 2003 extended play, Memorial Address. ("Ourselves", "Greatful Days", and "Hanabi: Episode II" were included in Memorial Address.)^[2] & follows the releases of Hamasaki's previous extended plays; Nothing from Nothing (1995),^[3] A (1999),^[4] and H (2002).^[5] Hamasaki did not release another extended-play single until Five in 2011.^[6] & was released in two formats: a stand-alone CD and a digital EP.^[1] The artwork for the EP depicts Hamasaki posing in front of a cloudy backdrop, with the title of the work superimposed over her hair.^[1]

& opens with the first track, "Ourselves", which is an R&B tune with influences of "exoticism pop".^[7] The lyrics describe Hamasaki's "painful" sense of sorrow and love.^[7] "Greatful Days" is a "refreshing" pop song that showcases Hamasaki's "festive" nature, her "pastel" vocals, and a "relaxing" positive message of happiness.^[7][8][9] "Hanabi: Episode II" is an answer song to Hamasaki's 2002 song, "Hanabi".^[5] It describes Hamasaki's "miserable" state and "struggle[s]" that is transformed into strength.^[9][7] "Theme of A-Nation 03" was used for the Avex A-Nation concert tour in 2003, and emphasizes traditional Japanese instrumentals, progressing more oriental J-pop sounds.^[7] The next three tracks are instrumental versions of "Ourselves", "Greatful Days", and "Hanabi: Episode II".^[1]

"Ourselves", "Greatful Days", and "Hanabi: Episode II" all served as the EP's promotional singles, released on July 9, 2003; the singles did not chart in any Japanese music charts. The singles were promoted through different endorsements deals in Japan; "Ourselves" was used as the televised theme song for Japanese cosmetics brand, Visee, and "Greatful Days" was used as the theme song for Hamasaki's 2004 TV series, Ayuready?.^[7] However, by the time the promotion of &, Memorial Address, and her 2003–2004 arena tour was complete, Hamasaki had grown dissatisfied with her position in Avex; she felt that the company was treating her as a product instead of a person.^[10] Although Hamasaki initially supported the exploitation of her popularity for commercial purposes, saying that it was "necessary that [she is] viewed as a product", she eventually opposed Avex's decision to market her as a "product rather than a person".^[11][12] All three songs featured an accompanying music video, which were included on several DVD compilations by Hamasaki.

& received favourable reviews from music critics. A reviewer from CD Journal commended the EP's production, and highlighted all the singles as stand out tracks; the reviewer highlighted its "music quality" as a positive note.^[7] Kondo Yang from Listen Japan was positive in his review, stating that & was a sign of growing "maturity" in Hamasaki's music. He also felt that her "charisma" and "personality" was a reason why & became successful.^[8] Eri Kato from Hot Express was positive in her review, commending Hamasaki's songwriting and composing skills, particularly with "Hanabi: Episode II", and the music arrangements. She later praised them as "unique masterpieces" and ^[9] Alexey Eremenko, who wrote the biography for Hamasaki on AllMusic, highlighted "Ourselves" and "Greatful Days" as one of the stand-out tracks of the extended play and Hamasaki's long career.^[13]

On the Japanese Oricon Singles Chart, & reached number one on its debut week, her third consecutive EP to have reached number one, and her sixteenth number one single overall.^[14] The EP lasted sixteen weeks in the top 100, selling 680,000 units,^{[15][upper-alpha 1]} and was certified double platinum by the Recording Industry Association of Japan (RIAJ) for shipments of 600,000 units.^[16] & is Hamasaki's final single to sell over 600,000 units, and her only post-single to achieve a close achievement of the limit is "No Way to Say" with 400,000 physical and digital sales.^[15][17][18]