BELLEVUE, Iowa — Through the years, Bellevue resident Ed Zaccaro has published educational textbooks on a wide array of topics, including various levels of math, science and statistics.

Despite the variety, a common thread has united his approach to each of the books — he wants them to be something that kids find fun and exciting.

“One of the things I truly believe is that excellence comes from passion,” Zaccaro said. “If I can get students excited about what they are studying, their performance will improve dramatically.”

Zaccaro and his wife, Sara, launched Hickory Grove Press in 2000. Since then, the company has published 14 educational books and has sold more than 250,000 copies.

The entire endeavor started with a volunteering gig. Ed recalls that he went to his son’s classroom and found it difficult to teach math using the materials he was given.

This sparked a bit of spontaneous creativity.

“I couldn’t find a good curriculum, so I decided to make my own,” he recalled.

Realizing that he might have stumbled upon something of substance, Ed sent his first book — titled “Challenge Math” — to publishing companies. A few decided to carry the book in their catalogs, fueling sales and compelling Ed to continue crafting more books.

Sara recalled that the first book used clip art and featured characters that brought the teachings to life. This became a trademark of Ed’s books and, in Sara’s view, a key to his success.

“I think the reason they’re so good is because he makes them fun,” she said. “They have art in them, and they have little characters.”

The books published by Hickory Grove Press generally put forth a curriculum, or a guide, for helping students navigate the complexities of learning something new. The books aren’t meant to completely redefine an existing curriculum but are intended to supplement the education materials that students have at their disposal.

Ed previously taught adult education classes to high school dropouts and those trying to obtain their GEDs. But he came to the realization that he could write books full time.

“By the third or fourth year, I realized I had enough money coming in that I could focus on this,” he said.

Ed augmented income by appearing at conferences and workshops, at which he talks about the content in his books and his approach to teaching.

Sara has played an integral role along the way. She sells books at conferences and works with wholesalers and distributors to make sure Ed’s books appear in as many places as possible.

The Zaccaros ultimately sold the rights for their books to be republished in Korean, Vietnamese and Chinese.

“It is very fun seeing the books in another language,” Sara said.

Through the years, the Zaccaros forged relationships with a variety of printing partners.

They had a lengthy relationship with Quebecor Printing, a Canadian printer that long had a physical presence in Dubuque. That company later changed its name to World Color Press before closing its Dubuque operation.

In recent years, the Zaccaros struck a deal with Amazon, the forum on which the vast majority of their products have sold. Under the pact, Amazon arranges for books to be printed once they are ordered.

Sara, though, emphasized that local partners also have played a vital role in pushing the business forward. She specifically cited River Lights Bookstore, which has long carried a wide variety of Hickory Grove Press textbooks.

In the early going, Ed focused his books on mathematics, which isn’t a surprise given his background.

He noted that his father was a mathematics professor, and as a result, he always felt like he was surrounded by it

“Math is in my genes,” he said.

Even so, he started to branch out, writing books on topics such as science. Whatever the topic, though, Ed found that his passion drove his production.

“When I am writing a book, I get consumed by it,” he said. “There are times when I have worked all day, every day for two months.”

Two decades into the family business, Ed and Sara occasionally stop to reflect on the great strides they have made. At its core, Hickory Grove Press is a simple operation — operated out of the Zaccaros’ home and benefiting from contributions from the whole family.

“It really is a family business,” Sara said. “It has primarily been Ed and I, but all three of our children have also helped out along the way.”

Ed said he always kept families in mind as he has created his books. He wants to make them accessible, something that can be a bridge to more complete learning.

“With reading, parents know they need to read to their kids,” he said. “People don’t know what to do about math. I want my books to help them.”