The picaresque novel follows Paul, a 23-year-old who discovers that he can shapeshift and uses this ability to alter his gender expression while wandering the United States.

He is a flâneur who enjoys wearing performative outfits and seeks out various sexual experiences with a diverse assortment of partners; his gender identity is never made explicit.

They had just quit a corporate job and began exploring creative writing while working at a bookstore,[3] taking a night class at Gotham Writers' Workshop.

[2] Despite the limited initial printing, the novel was reviewed in the "Briefly Noted" section of The New Yorker, which Lawlor said prompted widespread interest in the book as well as potential film rights.

Lawlor was subsequently able to begin working with literary agent PJ Mark, who negotiated a deal for broader publication with Vintage Books.

He uses this ability to change his gender expression, sometimes for sexual purposes, while adventuring across the United States[3][5] and avoiding voicemails from his first love who has been diagnosed with HIV/AIDS.

[9] Settings include the punk subculture of Iowa City, the Michigan Womyn's Music Festival, Provincetown, Massachusetts in the off-season,[5] and a leather bar backroom in Chicago.

The novel opens with him shapeshifting his body to have breasts and a vagina, dressing in feminine clothing, and going out to a bar while looking like "the girl he wanted to fuck".

When Diane breaks his heart, he becomes a man once again and travels to San Francisco, continuing to seek out sexual experiences including giving an outdoor blowjob to a "dirty hippie".

[11]: 159  Cultural and academic figures from the period are mentioned in the text as well, including theorists Lauren Berlant, Leo Bersani, and Judith Butler as well as others like Rainer Werner Fassbinder, Jean Genet, and Jeanne Moreau.

The review argued that the book's "unapologetically queer" nature should not hinder its mainstream success, describing Lawlor's writing as "evocative and urgent".

[12] The Saturday Paper described protagonist Paul as "an enfant terrible with heart", and the novel as "a sassy read, skilfully balancing humour with pathos".

[16] A review in Vice focused specifically on the role of music in Paul Takes the Form of a Mortal Girl, praising Lawlor's accuracy and attention to detail in selecting songs and artists to mention.

[8] The Los Angeles Review of Books described Paul as an exciting character, praised the novel's "gritty and uninhibited sexuality", and concluded that "Lawlor has written an intoxicatingly rousing masterpiece".

[7] Rain Taxi also praised the text in a review that noted its "warm tone and livewire voice" and its "nuanced treatment of a conceit that could easily yield to gimmick or cliché", concluding that "Lawlor is a magician, and a very good one".

[21] Booklist reviewed the novel as "a coming-of-age fairy tale without the easy moral, a mix of comedy and tenderness and backroom sexual exploits", and praised the author's use of genre.

[2] A Lambda Literary Foundation review stated that "Andrea Lawlor has coolly escorted sex back into conversations about gender, which have long been unmoored from fucking in the name of mainstream didactics and respectability", praising the novel as "an intelligent and dashing work ".

[24] The F-Word published a review describing Lawlor as "a brilliantly astute writer" and stating that Paul "reads like a cult classic from the beginning".

[11]: 159  The article concludes that "in his ardent receptivity to life, [Paul] offers to the reader a vision of boundless appreciation for the liminal, magical naturecultures of queer spaces and subcultural movements in American history".