"I get letters with 76 exclamation marks," the writer said. One child wrote, "I'm seriously in pain waiting for your next book."
Breitrose's books, "Mousenet," published in 2011 and "Mousemobile," out this month, — aimed at 8- to 12-year-olds — concern an adventurous girl who allies herself with a nation of computer-savvy mice to spread the word about climate change.
Getting her first book published was "murderous," she said, but after nearly a decade of submitting and rewriting, "Mousenet" came out under the label of Hyperion Books, part of the Disney Book Group, in 2011.
With two published books — and a third accepted just last week — Breitrose now has her eyes on a series. "They (the publishers) have book three, book four I've just this minute finished, and I'm trying to think of a plot for book five," she said.
After a long career of writing and editing for others, mostly in the field of health education, the British-born Breitrose relishes writing books of her own.
"I'd always thought I wanted to write something. I thought maybe it would be a detective story of the English model, but that didn't happen, so I tried a children's book," she said. Recalling that her now-adult daughter had been a reluctant reader — "it was torture getting her to read anything," Breitrose recalled — she aimed to write something that would get the attention of such children today.
Breitrose finds she does her best work, conjuring up plots involving intelligent mice, a feisty girl and the challenges of climate change, at the kitchen table of her longtime home on a quiet cul-de-sac of the Stanford campus.
"One problem with age is that I can't work all day," she said. "My brain works in the mornings, but after two hours I find that the edge is gone and it's better not to bother because what I write is not going to be my best stuff."
Generally, she writes in her bathrobe, between 7:30 and 9:30 a.m.
"Henry's trained not to speak to me," she said, referring to her husband of many years, retired communication professor Henry S. Breitrose, who established Stanford's graduate program in documentary film and television.
Breitrose grew up in the southeast corner of England — Winnie the Pooh country — tromping around Ashdown Forest just like Christopher Robin.
After graduating from Cambridge University, she worked for the children's magazine "Robin" and as a writer and director for the BBC before following her husband to Stanford, where they built their house in 1970.
With two children and a part-time writing career — for many years with the Stanford Heart Disease Prevention Program and later as a ghost writer for others — Breitrose always told herself she'd write her own book if she had the time.
But once she finally sat down to try, around 2000, she found, "I really didn't know how to do it. So I taught myself."
"It's pretty hard getting a children's novel accepted — it's murderous," she said. "Agents tell me that they take on maybe 1 percent of people who apply to them, who want to be their client. I was very lucky."
Breitrose's first queries to "a bunch of agents" in 2002 met with silence, except for one who did want to see the manuscript.
"He didn't take it on but never told me why and I was too shy to ask, because I really didn't want to know," she said. "I guessed what was wrong in his mind and I rewrote it, sent it back to him again. And again he didn't take it and didn't tell me why, but he did hand it off to a junior who got in touch with me.
"She told me what was wrong and I adjusted it but she still didn't like it. She liked the mice, but my humans weren't coming alive for her. So I rewrote it three times, each time a little better.
"And each time I sent it off to agents and guessed what was in their minds, because they didn't tell you."
Breitrose said a turning point came in 2007, when she and her husband were traveling in Holland and met with a former student of Henry's.
"She's very new-age and she asked, 'What would the mice actually do if they had the power of computers behind them?"
Up to that point, Breitrose's manuscript did not have the environmental angle, only that the mice would use computers for the general good, to help out humans.
"But at the time she asked that, I was very environmentally agitated — it was just after 'An Inconvenient Truth' came out — and I said, 'They'd fix climate change.'"
That theme seemed to add the magic touch. Breitrose returned the manuscript to the first agent she'd approached back in 2002, who passed it to a colleague who sold it "with not too much trouble" to Hyperion.
Now mulling a plot for book five, she's considering a fictionalized version of the Keystone Pipeline controversy and "something really big — really major — that the mice will take on.
"I have an ending scene, but I have to somehow get up to it," she said. "Climate change? It's a little hard to think that far ahead because that could be four or five years from now, but I think it probably will still be with us."
Breitrose will discuss her latest book in an event for youth Tuesday, Oct. 15, at 7 p.m. at Kepler's Books, 1010 El Camino Real, Menlo Park.