Earlier this year, Lisa Rao, an editor at Simon & Schuster, saw a segment on Good Morning America moments before she walked into an editorial meeting.

“I had my iPad and pulled up the clip and told them, ‘You have to watch this,’ ” Rao recalled about a story that involved a Walmart employee in suburban Sacramento, Calif., who found a spiral-bound notebook that contained 157 rules handwritten in a childlike scrawl. The book had nothing in it to identify the owner; Raymond Flores, a Walmart associate charged with corralling shopping carts, had found it in the parking lot. But he flipped through it and decided it could not have been discarded intentionally after reading rule no. 154: “Protect this rule book.”

So Flores, 20, posted a photo of the book on his Facebook page, hoping to reunite book and author. No luck. Then he contacted the local Fox TV affiliate. That story got picked up nationally.

By the time Rao and the rest of the S&S editorial team watched the GMA report, one thing was abundantly clear. “Our publisher, Valerie [Garfield], said immediately: ‘We must find the owner!’ ” And when Rao did, she offered the – co-authors, it turns out – a contract. And this October Simon & Schuster will publish Isabelle and Isabella’s Book of Rules, a jacketed hardcover in a “gifty” trim size, written by Isabelle Busath, age 10, and Isabella Thordsen, age eight, with illustrations by Priscilla Burris.

“The minute I saw the handwriting and heard all the hysterical and the sweet rules these two had written, I knew I wanted to publish it,” Rao said. “ ‘Don’t bite the dentist?’ How could you not want to publish that?”

Isabelle and Isabella created the rule book last Christmas break as an attempt to teach their younger siblings the ropes. “They had been coloring with crayons and one of the younger kids wrote on Isabelle, so one of the rules became ‘Don’t color on PEOPLE,’ ” Rao noted. “They had the sweetest of intentions.”

The text will be recreated pages from the girls’ journal in their own handwriting and original spelling. “We felt like it made it even more sincere if we kept their misspellings,” Rao said. “One of the rules is something like, ‘If you want something, don’t wine.’ Who would want to take that out?” Rao did edit out a few duplicates. The girls had taken turns making entries and both thought “Don’t waste paper” was a good rule to live by.

Once reunited with their book, the cousins immediately added rules they had thought of since they’d lost it. Rao says the published book will contain about 200 rules. Will one of the new ones be, “Let your mom check Facebook whenever she wants?” (Stories about Flores’s quest to find the book’s owner eventually appeared in Isabelle’s mother’s Facebook feed, which is how the book finally found its way back to its authors.) Or “Don’t trust the rule book with just anybody?” (After her pen exploded, Isabelle gave the book to a friend to hold while she went to wash her hands. The friend accidentally dropped it getting into the car in the Walmart parking lot.)

Maybe it will even include the one rule the girls let somebody else write in their book – their new hero, Raymond Flores. His rule was simple: “Stay in school.”