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.

Hamasaki contributed by writing the lyrics to all the tracks, while Japanese production and manager Max Matsuura served as the EP's main producer.

& 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.

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] The artwork for the EP depicts Hamasaki posing in front of a cloudy backdrop, with the title of the work superimposed over her hair.

[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] 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.

The music video for "Hanabi Episode II" depicts Hamasaki on a grey beach set and in the end sparks start falling behind her.

[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.