In addition to the titular short story which appeared in Akita Shoten's Princess, the anthology includes "4/4 [Quatre-Quarts]" and "X+Y"—both of which were serialized in the Shogakukan magazine Petit Flower.

Set in a shared futuristic universe,[1] the stories' common thread is a genetically-engineered "Unicorn" species created for space travel.

After he saves a Unicorn descendant named Trill from a free fall, he frequently visits her in the home of Professor Sazzan, the man who adopted her.

When Sazzan tries to assault Trill she breaks a vase on his head and runs to an airlock, where she falls to her death in front of Mori, who is aboard a ship leaving for Mars.

His father, Doctor Moonsault, had developed a sex-change drug with an intended temporary effect; however, when Marble took it she remained a woman for three years.

[5][6] The English version of the stories appeared in the Viz Media magazine Manga Vizion: "A, A Prime" in April and May 1995, "4/4" in July and August and "X+Y" in four installments from October 1995 to January 1996.

By undermining the reader's sense of gender and applying scrutiny to the interpretive structures related to it, she is calling into question the very conventions that define the work that they are reading.According to the back cover of the Viz Media edition, the Unicorn's "personal struggles" are a metaphor for human alienation in contemporary society.

[10] Usually, wrote Thorn, Hagio's stories center "on a remarkable and strange character who [...] seems incapable of so-called 'normal' human interaction" until a "straight man", "unsure of his place in the world, and just trying to muddle through [...] forms a unique bond with the 'eccentric.

[12] Manga Bookshelf's Katherine Dacey wrote: "One of [its] most striking themes is the relationship between memory and identity", demonstrated by "A, A Prime" and the character of Tacto.

[13] In the Comics Journal, Rob Vollmar wrote that Hagio gives "4/4" and "X+Y" a shōnen-ai beat and explores gender ambiguity; in "4/4" Mori is depicted as hyper-emotional, and Trill (a woman) has no feelings.

[11] Steve Whitaker, for The Slings & Arrows Comic Guide, called A, A Prime "a masterful example of science fiction in a shojo", praising its art: "Facials and montages are carefully played-off against the portrayal of the various planets and their communities".

[15] Describing the anthology as a "flawless jewel of science fiction", Shaenon K. Garrity called it an emotional work which touched her deeply: "Because of A, A Prime, I discovered that this art form could do more than I'd imagined—not just tell ambitious stories, which I already knew from reading Sandman and Bone and Watchmen, but tell them with passion, in lines drawn from nerve endings, using every weapon in the artist's arsenal to not just dazzle the mind, but stab straight to the heart.

Dacey cited Hagio's "unique ability to mix the sublime with the ridiculous", such as the characters' names and costumes and the sex-change drug.

[8] It was cited by Garrity as "one of the forerunners to countless modern manga with inventive gender-bending elements", such as Rumiko Takahashi's Ranma ½.

Another Takahashi work, Urusei Yatsura, has a storyline in which clones are differentiated from the originals by apostrophes on their heads, referring to "A, A Prime"'s title.