When the president of the National Writers Union heard how much Baltimore Mayor Catherine E. Pugh had been paid for her children’s books, he paused.

“What?” said Larry Goldbetter, who has led the union for a decade. “No way.”

Pugh (D) has been paid nearly $700,000 for her self-published “Healthy Holly” series by businesses intertwined with the government she has overseen — a figure that has raised eyebrows in the world of children’s book publishing, where it can often be hard for even full-time authors to make a living.

Facing a groundswell of criticism and a request by Gov. Larry Hogan (R) for an investigation by the state prosecutor, Pugh took an indefinite leave of absence Monday, citing health concerns.

Hogan wants a probe into Pugh’s book deal with the University of Maryland Medical System, which paid her $500,000 for a total of 100,000 books.

“It’s crazy to wrap your brain around a six-figure number of books being sold,” said Wendy Dean, who owns Baltimore-based Omnibus Publishing, which focuses on children’s books. “To sell 100,000 books — that is your ultimate goal. . . . It feels like that would be equivalent to being on the New York Times bestseller list every week for a year.”

Dean estimated that a big publishing house working with a first-time author might sell and distribute 10,000 books, although she said numbers vary , especially for self-published books.

UMMS paid Pugh for five orders of 20,000 books each, beginning in 2011, when she was a state senator who served on a committee that partially funded the hospital network, the Baltimore Sun first reported.

She returned $100,000 for the last order in the series, which she said is not complete.

The Sun also reported that Kaiser Permanente paid Pugh more than $100,000 for about 20,000 copies and that Associated Black Charities paid her $80,000 for 10,000 copies.

The Maryland Automobile Insurance Fund, a quasi-public company created by the legislature, gave $7,500 in 2012 to Pugh’s Healthy Holly LLC, according to the fund’s executive director. At the time, Pugh was a state lawmaker who sponsored legislation favored by the fund. The next year, the fund gave $5,000 to Associated Black Charities, which was collecting money for “Healthy Holly” books. The fund’s donations were first reported by the Sun.

Pugh attorney Steve Silverman did not respond to questions about these deals.

On Tuesday, Baltimore City Council member Ryan Dorsey asked Baltimore Inspector General Isabel Cumming to investigate the bidding and awarding of a $48 million contract that Kaiser received from the city in 2017, when Pugh was profiting from her book deal with the company.

Kaiser spokesman Scott Lusk did not respond to questions Tuesday but said in a statement Monday that Kaiser’s purchase of the “Healthy Holly” series came nearly 30 years after the company was selected to provide coverage for city employees and “has no connection with our commitment to continue offering our care to Baltimore City government employees.”

Dean, who has lived in Baltimore since 2002, said she has spoken in recent days with some in the children’s book industry who are upset by the size of Pugh’s contracts.

“There is frustration, especially on the authors’ end,” she said. “This is what they do for a living. They put their blood, sweat and tears into this, and they still might not make a living.”

Children’s book author Christina Allen, who runs a small publishing house in Lexington Park, Md., said she had never heard of orders as large as Pugh’s for first-time authors of picture books.

“Whoa,” Allen said. “That is an impressive number of books.”

Allen said her first book, about a rare breed of turkey on her farm, sold about 8,000 copies. “I don’t make any money,” she said. “I’m doing it because I enjoy it. Maybe I’ll make money one day.”

Elected mayor in 2016, Pugh earns $178,000 annually. She also owns a boutique clothing store. In 2005, she wrote a poetry book titled “Mind Garden: Where Thoughts Grow.” A copy of that book is for sale on Amazon for $100.

The “Healthy Holly” books follow the adventures of an African American girl named Holly and are intended to promote healthy living.

Pugh spokesman James E. Bentley II referred “Healthy Holly” book questions to Silverman. He said the mayor, who had a recent bout with pneumonia, is “at home, trying to get well.”

Pugh said at a news conference last week that the deals with UMMS were a “regrettable mistake.” An independent audit of the medical school system and contracts made by its board members began Tuesday, interim chief executive John Ashworth said.

Pugh used a Canadian printing company to complete the first three orders for UMMS. She showed shipping manifests for those orders at the news conference.

Joseph Cohen, vice president of Kromar Printing in Winnipeg, Manitoba, said his company was paid between $13,000 and $15,000 for each of the 20,000-book orders it completed. He said that price range is standard for picture books between 28 and 32 pages.

He said his company was not asked to print a fourth batch. Pugh said at the news conference that it recently came to her attention that the fourth order of books had been delayed and was not completed.

“We’re just the printer,” Cohen added. “It sounds like we got caught up in a pretty big story.”

The controversy swirling around Pugh comes as Baltimore is struggling with a surge of violence that officials have struggled to address. Homicides have topped 300 for four straight years, even as homicide arrest rates have plummeted, and there have been five police commissioners in as many years.

Baltimore City Council President Bernard C. “Jack” Young (D), the acting mayor, told reporters at the Maryland State House on Tuesday that Baltimore “is in good hands.”

“I’ve been doing this for the last 21 years, making them wheels turn,” said Young, who has served on the council for more than two decades and said he will not run for mayor in 2020. “It’s going to continue to turn.”

Erin Cox contributed to this report.