ST. LOUIS — Business schools are often eager to teach about two ends of the spectrum: Massive, Fortune 500 companies and small, fast-growing startups.

“We are always thinking,” said Michael Mazzeo, “’What’s the next unicorn?’”

Mazzeo, the new dean of Washington University’s Olin Business School, thinks more attention should be paid to the vast and under-studied middle ground.

Small and mid-size firms are often overlooked in academia, but full of rich, teachable lessons, Mazzeo said. And many of those businesses are in a period of transition, as the families who own them make decisions about whether the next generation will take over.

It’s a philosophy honored in a book Mazzeo wrote with two other business professors. The trio embarked on a series of road trips across the U.S., interviewing owners and managers at small and mid-sized medical, manufacturing, hospitality and retail businesses.

They documented their findings in their 2014 book, “Roadside MBA: Back Road Lessons for Entrepreneurs, Executives, and Small Business Owners.” The group received an Emmy nomination for a series of videos they made promoting the book.

The professors found case studies on business expansion in an Arkansan orthodontics chain, hiring practices in a Missouri bowling alley, and product differentiation in a Kentucky women’s gym, among many, many others.

One of Mazzeo’s favorite examples to teach came from a visit the group paid with a fire hose manufacturer in Dothan, Alabama. The company used massive looms, which can’t be used for any other purpose than making fire hoses (and, allegedly, produce “more noise than The Who circa 1969,” the book says). The sizeable, up-front investment in the equipment becomes a lesson about sunk costs and barriers to entry.

The businesses they visited, Mazzeo said, yielded simple, elucidating examples of important economics concepts. And the stories are unique, which helps students remember the principles behind them.

Mazzeo said that in the academic community, some viewed the book as unserious. But he recalled that after it was released, he spoke to one business owner who had unexpectedly inherited a small business from his parents. The man told Mazzeo that he didn’t think he could run the business, until he read the book.

“Nobody’s going to say that based on my Econometrica paper,” Mazzeo said with a laugh, referring to an academic journal.

He officially started in his new role on Sept. 1, after 25 years at Northwestern University’s Kellogg School of Management, both as a professor and senior associate dean of curriculum and teaching.

When the Olin opportunity came along, Mazzeo said, he messaged everyone he knew from Washington University over LinkedIn, and asked them to tell him about the school, and life in St. Louis.

He’s eager to dive into the St. Louis community. By the end of his second week at Washington University, he’d attended two Cardinals games and two St. Louis City SC games. He brings with him a sense of joy around business.

“Work gets such a bad rap for being like drudgery and a chore,” he said. “I think my job is a lot of fun.”

As an openly gay person in a position of leadership, he hopes to be visible so that other LGBTQ+ people feel more comfortable in the business world, and imagining themselves on similar career paths.

“For many gay people, hiding is a part of what they feel like they need to do in a professional environment,” Mazzeo said.

Originally from Poughkeepsie, New York, Mazzeo holds a bachelor’s degree and a doctorate from Stanford University.

At one point during the recent interview at Mazzeo’s office, the reporter signaled that a tough question was about to be asked. Mazzeo knew exactly what was coming.

“This is something about the Cardinals you’re going to ask me, right?” he said.

Yes.

How will Mazzeo manage his loyalty to the New York Yankees, as he lives and works in Cardinals town?

He can keep things separate, he said. They’re in different leagues. They rarely play each other.

Pressed on the issue, he smiled.

“I think,” he said, a little cautiously, “loyalty is extremely important.”