Ms. Mayer — “Yahoo’s Geek Goddess,” as Vanity Fair has called her — is not the first well-known executive brought in to reinvent Yahoo, but she certainly arrived with the most fanfare. When Yahoo hired her away from Google in 2012, she was only 37, making her the youngest woman to lead a Fortune 500 company. Valerie Jarrett and Nancy Pelosi were among those who called to congratulate her on her new job. Adding to the excitement was the news that Ms. Mayer was five months pregnant.

Expectations were high, to say the least. In Nicholas Carlson’s “Marissa Mayer and the Fight to Save Yahoo!,” we learn that when Yahoo’s new chief executive showed up for her first day of work, she was greeted by posters of her face, done in the style of Shepard Fairey’s Barack Obama poster — complete with the word “hope.” At Yahoo, they have a term to describe things that don’t feel like they should be part of the so-called user experience: “yawful.”

“Marissa Mayer and the Fight to Save Yahoo!” was excerpted in The New York Times Magazine, and in many ways it reads more like an overgrown article than a book. This is partly a function of Mr. Carlson’s informal tone and personality-driven approach. But it’s also a function of the subject. Yahoo is a big company, but it’s not what you would call an American institution, or even really a relevant force in our culture. And it’s not clear that there’s much more of substance to say about Ms. Mayer that hasn’t already been said in the many profiles of her.

That’s not to say that the book isn’t a lot of fun to read, or that Mr. Carlson isn’t steeped in his subject — an impressive feat considering that Ms. Mayer not only refused to cooperate with him, but actively interfered with his research and reporting. During her first day on the job at Yahoo, he writes in one of the news bites touted in the book’s news release, Ms. Mayer apparently mistook the company’s general counsel for the I.T. guy.

Mr. Carlson, the chief correspondent for Business Insider, a website that covers technology and finance, doesn’t waste words lingering over details or musing on bigger themes — leadership, technology, the nature of innovation. He favors the short paragraph and the brief biographical sketch. “She was a pompom girl and a debater,” he writes in his précis of Ms. Mayer’s childhood. “She was on the precision dance team.” The result, to borrow the digital media cliché, is corporate history as snackable content.

Today’s Yahoo is a sprawling hodgepodge of products and services, none indispensable. It is a company adrift, a well-capitalized mess. But as Mr. Carlson reminds us, Yahoo was a pioneer of the Valley. In its earliest incarnation, Yahoo was the digital equivalent of TV Guide, providing an advertising-supported directory of web pages for the still nascent Internet. Before it became known as Yahoo, it was called David and Jerry’s Guide to the World Wide Web, after the company’s founders, David Filo and Jerry Yang.

They had no trouble monetizing their new business. Yahoo nearly tripled its revenues from 1997 to 1998. Its founders became very rich, very quickly. “It takes a female elephant 22 months to gestate a calf,” Mr. Carlson writes. “Filo and Yang made their first $100 million in less than half that time.”

For a little while, anyway, the Yahoo logo was everywhere — on Ben & Jerry’s ice cream containers, on Visa cards, on the Zamboni machines at professional hockey games. Then things started to fall apart. Yahoo was the victim of larger economic forces, specifically the bursting of the dot-com bubble in 2001. But it also failed to evolve or innovate. As such, it gradually lost market share to its growing number of competitors. And it became deeply uncool, the Reebok to Google’s Nike.

Enter Yahoo 2.0, the first of many attempts to turn around the company. The names, at least, would get more creative. There was, for example, Project Godfather, the 2002 plan to rub out Yahoo’s competition in the Internet search business. Several years later the company resolved to stop spreading itself so thin, like peanut butter. The Wall Street Journal labeled this Yahoo’s Peanut Butter Manifesto.

In Mr. Carlson’s breezy retelling, these hapless efforts to recapture the company’s former glory amount to almost comic exercises in futility. Yahoo is Silicon Valley’s version of the New York Knicks. Its string of well-compensated leaders can’t seem to get anything right. Presented with the chance to buy Google for $1 million in 1997, the company passed. Years later, it could have had Facebook, which is now valued at more than $200 billion, for $1 billion. Yahoo drew the line at $850 million.

Ms. Mayer emerges from this book’s pages less as a Geek Goddess, or even a computer science nerd made good, than as a kind of cyborg, a tone-deaf workaholic who has trouble making eye contact and requires only four hours of sleep a night. In other words, it turns out she’s no different from your stereotypical male tech executive. Mr. Carlson describes her management style as “dictatorial” and her manner of speaking as “staccato verbosity.” At one point, he goes so far as to suggest that she may have Asperger’s syndrome. Mr. Carlson issues a similarly harsh judgment on Ms. Mayer’s tenure at Yahoo. Among many other things, he faults her for trying to take the company’s “middle-America, Walmart-esque brand” upmarket by hiring Katie Couric as its Global Anchor for $5 million a year. As Mr. Carlson recounts it, the decision was prompted by a breakfast with the Vogue editor Anna Wintour, who described Yahoo’s women’s site as “dreadful.”

Wall Street seems to agree with Mr. Carlson’s assessment. Yahoo has a market capitalization of about $44 billion. But when you take out its large investment in the Chinese Internet company Alibaba, Yahoo’s core business is currently being valued at less than zero dollars.

Ms. Mayer is still running Yahoo, though it’s anyone’s guess how much longer she will remain. The company’s last chief executive was deposed by the head of a powerful hedge fund with a large position in Yahoo. In the book’s final pages, Mr. Carlson writes about a similar campaign introduced recently by a major stockholder who criticized Ms. Mayer for failing to cut costs and for spending too much on acquisitions that haven’t added to revenues. This stockholder said the smartest thing for Yahoo to do at this point would be to sell off its assets and return the proceeds to shareholders.

Maybe the fight to save Yahoo is almost over. Or maybe the company is just coming to the end of another losing season.