A little more than a year ago, I visited the Barneys Manhattan flagship store while it was in the final throes of its liquidation sale. It looked like the rapture had just happened. The pale beige carpet and matching velvet sofas were strewn with partnerless shoes and discarded pieces of trash, as though feral shoppers had tossed them on the floor when they lost interest.

I was, admittedly, shocked: The department store had always been, for me, a bastion of ’90s-era luxury and sophistication, elegant if mostly unaffordable. In retrospect, its demise was perhaps a harbinger of the bizarre new world to come. Barneys now feels like an artifact of a bygone era.

As does Simon Doonan, who was creative director of Barneys for more than three decades, and the mastermind behind its memorably outré window displays. I mean this as a compliment. Into this tech-heavy, bleakly monotonous moment we are now living through, he arrives with a pragmatic, rather old-fashioned perspective that feels as bracing as an ice bath.

In the first of his two recent books — he has written 11 — “How to Be Yourself: Life-Changing Advice form a Reckless Contrarian” (Phaidon), Mr. Doonan, who calls himself “an extremely skeptical self-help guru,” advises people to step away from the screens and take time to discover, cultivate and express one’s authentic inner person.

Social media, he writes, is “a distraction from the real work, the heavy lifting, the development of your true self” — an almost radical opinion at a time when TikTok creators are treated as auteurs.

Mr. Doonan is like your bossy, eccentric uncle with perfect taste and inflexible ideas. “I do not have kids, but like many aging baby boomer nonparents,” he writes, “I am an expert on parenting.…”

The book, a fun little trifle that includes numerous photos and large-print quotes from various celebrities (Keith Richards to E.B. White, Andy Warhol to Lizzo) on primary-colored pages, is written in a snappy, entertaining, Diana Vreeland-esque style.

On family: “I see siblings as functional items.”

On wearing black: “At one point, it meant you were a radical outlaw; now it means you work at the MAC counter.”

On Prince Harry and Meghan Markle naming their son “Archie,” and how it has endeared them to the public: “It was as if they threw 500 years of encumbering European history out the window and gave him a dachshund name.”

The advice he dispenses is the kind of unvarnished, unapologetic counsel one doesn’t often get these days, when people are afraid of offending, well, anybody.

But Mr. Doonan, whose working-class parents dropped his sister and him off at an orphanage for affordable day care (“Welcome to my Little Dorrit years”) — and who held multiple factory jobs before landing his luxury department store post — has guidance that is sensible, useful and refreshing: Pay your bills. Show up to work early. Get your hands dirty. “Put down your phone, leave the house, and start walking,” he writes.

But how to be oneself once you’ve put down your phone?

Like a ’50s housewife, Mr. Doonan believes one should start with the exterior. He calls vanity “a life-affirming force, a gesture of creativity and optimism, an antidepressant with no bad side-effects,” and he urges readers to put time, effort and imagination into their appearance, an endeavor that can involve tailoring one’s clothes, adopting a particular hairstyle, or alighting on a signature flourish — in Mr. Doonan’s case, flower printed button-down dress shirts in Liberty of London fabric.

When it comes to décor, he is similarly unforgiving, asserting that “not giving a toss about your décor is a crime against humanity, a missed opportunity for you and a source of PTSD for others.”

Are you an “emperor of camp” like Liberace, a burlesque queen living in “a satin upholstered jewelry box” like Dita von Teese, or so idiosyncratic that you belong among “the unclassifiables,” à la Phyllis Diller, who has a room dedicated to her wigs? It doesn’t matter, as long as your home is an aria of personal expression. Lack of money, he adds, should not be an obstacle, since, in aesthetic matters, it tends to be inversely proportional to taste.

THE PROBLEM with many self-help books is that they are gauzy and vague, their principles deracinated from any real-life examples. “How to Be Yourself” mostly avoids this common pitfall, as Mr. Doonan takes readers on an anthropological tour of people he admires and includes mini-histories of influential mentors.

Still, reading the second book Mr. Doonan recently published, “Keith Haring,” about the prolific late artist, underscores an idea I have long held to be true: Biography is the best self-help. The principles of living arise organically from the story of an exemplary life — or from a life that was not so exemplary. The lessons have not been detached from their origins.

In this slim volume, Mr. Doonan recounts the story of a driven young man from the small town of Kutztown, Pa., who drew compulsively from a young age, dropped out of commercial art school, and moved to New York City in 1978 “in search of intensity — sexual, professional, emotional, and artistic.”

Inspired by the graffiti movement, he started defacing public buildings and drawing his now famous cartoon iconography — the crawling baby, the dog, the flying pyramids, the dancing man — on vacant ad spaces in the subway. “Art,” he wrote in his journal, “is for everybody.”

In a few short years, he had gained a cult following, and by age 25, he was a world-famous pop artist in the vein of Andy Warhol. Like Mr. Warhol, he treated art as a business, and his Pop Shop, which he opened in 1986 out of an impulse to offer his art in the affordable form of T-shirts and buttons, was one of a kind.

Mr. Haring died from AIDS only a few years later, in 1990, at 31. His meteoric rise and intense, compressed period of productivity and fame — in 1987 alone, he had six solo exhibits and painted five public murals — seem to have been awaiting Mr. Doonan’s swift, jaunty approach.

Mr. Haring’s story is recounted in the present tense, as though the artist is Mr. Doonan’s friend or roommate. “Keith is now living a life of bohemian glamour and loving it. Although he never turns his back on ‘the people,’” Mr. Doonan writes, “his infatuation with fabulosity is undeniable.”

Mr. Doonan is a populist with a love of glamour, and you can see his deep admiration for Mr. Haring, whose path exemplifies certain ideas Mr. Doonan holds dear. Mr. Haring was, for example, impressively determined and resourceful, funding his art and his autodidacticism with a series of menial jobs.

After quitting the Ivy School of Professional Art in Pittsburgh, he found work as a dishwasher at a health food restaurant and as an assistant cook at the Fisher Scientific Corporation, then got a maintenance job at the Pittsburgh Arts and Crafts Center, where he attended classes informally and availed himself of the library there.

His willingness to do whatever it took, Mr. Doonan writes approvingly, “is a measure of his single-minded, uncomplaining approach to life, his resilience and his inability to accept defeat.”

Mr. Doonan also emphasizes that Mr. Haring had an “ability to extract ideas, beauty, philosophy and positivity” from even “crummy situations,” and indeed Mr. Haring had his first “show” while working at Fisher, on a wall in a cafeteria. It was announced in the weekly menu: “Keith is employed in our cafeteria.”

“Keith Haring” is an installment in Lives of the Artists (Laurence King Publishing), a collection of brief artist biographies inspired by Giorgio Vasari’s 16th century originals, which aim to discuss the life rather than the work.

But if this delightful book has a weakness, it’s that we are left with only a hazy sense of Mr. Haring’s art — the massive scale of his murals, the fluidity of his lines. This is, in part, a function of his process: “the whole sort of graffiti performance aspect,” as Mr. Haring himself put it. As with Jackson Pollock, it helped to see him in motion.

Yet Mr. Haring pictograms have also become so ubiquitous — appearing on posters, T-shirts, socks, Swatches, at Uniqlo — that it’s difficult to remember that the introduction of cartoons and graffiti into the realm of fine art once felt strikingly new. As did his treatment of serious issues, like AIDS and the crack epidemic, in bright, playful images.

The book doesn’t include photos of Mr. Haring’s drawings or murals, but there are many of the slim, sweet-faced young man who believed art was for the people, but who also really loved being famous — and didn’t see these as contradictory impulses. Neither does Mr. Doonan.