Late one Friday afternoon, while working in her office in downtown Milwaukee, Janie receives worrying news regarding her recent mammogram. Often afflicted by “low-level dread,” she expects the worst, accepts her lot and makes an appointment for further screening on Monday morning. Between now and then she attempts to keep calm and carry on. She confides in her best friend Pippa but doesn’t share her fears with her husband or teenage son. She also thinks back to happier, more carefree times at law school, and replays what turned out to be “the most intensely romantic moment of her life” with a barista she fleetingly knew called Silas. Back in the present, Janie is relieved to get the all clear with her health – but is then shocked to learn from Pippa that fate hasn’t been as kind to Silas.

“Show Don’t Tell: Stories” by Curtis Sittenfeld. Random House. 320 pages. $28 Random House

Curtis Sittenfeld’s story “Follow-Up” is one of 12 in her second collection, “Show Don’t Tell.” This tale has many of the same components as the others: It features a middle-aged, Midwestern female protagonist; it flits between two different narrative time frames; and it blends acerbic wit, shrewd insight and sharp-eyed observation to explore frustrated lives and the thornier, messier and grittier aspects of human relationships.

Sexual dynamics are scrutinized in “A for Alone.” Artist Irene conducts a mixed-media project that entails having lunch with a different man each week to disprove the “Mike Pence Rule” — the former vice president’s claim that it is inappropriate for a married man to spend time alone with a woman. Lunch with one man prompts Irene to question the validity of her project. Lunch with another leads her to muse on the state of her marriage — and embark on an affair.

Marital tension and the prospect of infidelity resurface elsewhere. In “The Marriage Clock,” Heather flies to Alabama to negotiate with Brock Lewis about the romantic comedy her film studio plans to make out of his best-selling marital self-help book. Brock calls marriage “a tough enterprise” and proves that is the case when he takes Heather out on his boat and out of range of his wife. The shortest story here, “The Hug,” revolves around Daphne’s decision to greet, and comfort, an old flame with an embrace, and her jealous husband’s reaction to it. What could have been an inconsequential tale of much ado about nothing is instead a bite-size drama that shows how small gestures can trigger complex emotions.

Some stories deal with reconnections. The last and longest story, “Lost but Not Forgotten,” reacquaints us with Lee Fiora, the main character of Sittenfeld’s 2005 debut novel, “Prep.” Rather than continue tracking Lee’s growing pains, class awareness and battles for survival at a prestigious Massachusetts boarding school, Sittenfeld presents her as older, wiser and luckier in love at a 30th alumni reunion. Meanwhile, in “The Tomorrow Box,” the collection’s sole story fronted by a man, a get-together with an old friend who has gone from gauche and geeky classmate to famous and successful life coach gives “downwardly mobile” Andy food for thought as to what constitutes a purposeful existence.

Other stories grapple with current concerns and moral sensitivities. “White Women LOL” focuses on a character who is forced to deal with the fallout after she falsely accuses a group of Black people of gate-crashing her friend’s party. In “The Richest Babysitter in the World,” a woman tells her family that she once turned down a job from a man who went on to become a Jeff Bezos-type billionaire. Asked by her young son why she buys products from his “kind of bad” company, she replies, “Because there’s often a gap between the people we aspire to be and the people we are.”

Such flaws render Sittenfeld’s characters more human and, consequently, more relatable. Again and again, we encounter individuals trying to make sense of their imperfections. Some regret roads not taken, others have made wrong turns or hit dead ends. One woman feels she has “journeyed into some kind of emotional instability, with one questionable decision begetting another.” Andy claims he leads “one of those lives that’s held together by duct tape and prayers.”

Occasionally Sittenfeld introduces a character by providing a potted biography — who they are, what they do, where they came from, how they operate. On the plus side, this allows a character to get up and running. However, these kinds of info dumps are clumsy, and they deprive us of the opportunity to discover characters for ourselves through their words, deeds and impulses. In these instances, Sittenfeld inverts the title of her collection — that writing adage — by telling, not showing.

Otherwise, it is hard to find fault with what is a bravura collection. Sittenfeld may demonstrate more creative risk-taking in her novels — particularly “Eligible,” her modern retelling of “Pride and Prejudice,” and “Rodham,” her reimagined life of Hillary Clinton — but what she displays in her expertly crafted and hugely engaging short-form fiction is, quite simply, supremely accomplished storytelling.

Malcolm Forbes is a freelance writer whose work has appeared in the Economist, the Financial Times, the Wall Street Journal and the New Republic.