"Swimming Studies," by Leanne Shapton Tennis is the loneliest sport, Andre Agassi has said. I'm willing to give him the benefit of the doubt, despite the persuasiveness of Alan Sillitoe's novella "The Loneliness of the Long Distance Runner." I wonder also if Mr. Agassi has reckoned with the solitude of competitive swimming. The talented illustrator Leanne Shapton, in her pointillistic and quietly profound new memoir, "Swimming Studies," recalls how, in 1988 and 1992, specializing in the breaststroke, she made it as far the Canadian Olympic trials. Ms. Shapton writes as confidently as she draws, and memorably conjures swimming's intense, primordial and isolating pleasures. She describes the sensation of being underwater and alone at a meet, the "loud then quiet, loud then quiet" of one's head rising above the waterline, how "a chorus of warbled pops and splashings bursts against the sides" of your cap. Between strokes, she says, "each swimmer can catch the deep bass of the announcer" resonating through the chlorinated deep. She notes how swimmers are made to feel not merely solitary but quite small. "Coaches stand above you, over you," she writes. You look up to them, are vulnerable, naked and wet in front of them. Coaches see you weak, they weaken you, they have your trust, you do what they say. Ms. Shapton is the author and illustrator of several previous books; she is also the former art director of The New York Times's Op-Ed page. With "Swimming Studies" she's composed a volume that is less a proper memoir than a collection of flickering sketches. It leaps from her training for the Olympic trials and becomes a treatise on swimming and pools in general. It's a sport that lingers in her mind and in her muscles. "I still dream of practice, of races, coaches and blurry competitors," she says. I'm drawn to swimming pools, all swimming pools, no matter how small or murky. When I swim now, I step into the water as though absent-mindedly touching a scar. My recreational laps are phantoms of my competitive races. Her book is sprinkled with her own spare illustrations, like the two pages of small ovals that represent odors she recalls from her swimming days. Among them: "Teammate's hair: Finesse conditioner circa 1987, released when hair is pulled out, damp, from a tight ponytail." And: "Sit-ups partner: Tide, milk, terrier, and grape Hubba Bubba." The black-and-white photographs she provides of her favorite swimsuits may start a run on vintage suits, the type she often wears. Ms. Shapton's prose frequently has the density of poetry. She notes how swimmers have the ability to "make still lifes out of tenths of seconds." A sunset is "Tahitian Treat pink" and "optical glucose." Boys at work making pool lanes are "a mini Iwo Jima tableau." In time for this summer's Olympic Games, her book is also a canny insider's look at competitive swimming, a sport she describes as "insular, clammy, circumscribed and largely underexposed." She walks her readers through changes the sport has undergone since her time, like the arrival of "technical suits, track blocks, false-start rules." She notes that the inverted-V formation that occurs in most races is because the fastest racers are placed in the middle, while the slowest are at the outside. "A swimmer who leads from lane one, two, seven, or eight," Ms. Shapton observes, "is often called "outside smoke." " Ms. Shapton's book contains its own kind of outside smoke. She pulls in unusual elements, odd stray memories. She writes about how Alcatraz and the Titanic disaster interest her from a swimming perspective. She imagines breast-stroking away from each. A section about aging leads her to recall a favorite, melancholy segment from "The Muppet Show," set to Jim Croce's "Time in a Bottle." In it, an elderly scientist makes bubbling concoctions in test tubes and grows younger as he consumes them. After the last drink he explodes, and sadly returns to his true age. The segment leads her to the yearning realization that, "After 20 years I still search for the dumb focus I had as a competitive swimmer." Some readers may find that "Swimming Studies" verges on the precious. It's an adorable book, self-consciously so, a boutique item that cries out to be sold on Etsy and next to the garlic scapes at organic farmers" markets. Others may be perplexed by an unexplained disconnect between Ms. Shapton's thrifty, middle-class Canadian upbringing - there is a funny bit about her family being too cheap to order appetizers in restaurants - and the luxurious and exotic life she seems to lead now. In this book she visits, and often swims in, cities like Turin, Paris, Reykjavik, Berlin and London. She swims on the private island of Mustique, in Morocco, and off a sailboat in the Aegean. She stays in a house once owned by Winslow Homer in Maine. She sleeps in fine old hotels. You may begin to confuse her with Sofia Coppola. Some of this travel is related to her work as an artist. But it helps to know that Ms. Shapton's husband - who is referred to only as James in her narrative, and who seems mostly benign and amused by her swimming obsession - is James Truman, the former editorial director of Condé Nast. Ms. Shapton is so smart and so likable that you will pass her book along to the swimmers in your life. Her experience underscores the truth of a T-shirt slogan she spies at a competition: "If swimming were any easier, it would be called hockey."