It's about the construction the Cathedral of Saint John the Divine (the Momma in the book is a stonecutter).
"Mara, with her beautiful writing, helped bring it to life," Steve Mooser said.
Nine publishers turned it down before Candlewick rejected it. The reason for the rejection: It was set in Manhattan and they didn't think anyone who lived outside of New York would be interested.
"It look for a long time that this story I had written was a failure," she said. "This was not a surprise to me. It was something I had accomplished many times before."
She shared the many ways she'd failed in the past, including one form rejection she received for a manuscript she'd submitted three years earlier.
"All this form rejection was made possible by SCBWI," she joked. "If you don't give up, eventually you end up selling some books."
"When we do succeed, when we do finish that book and it isn't horrible," she said, "that's when we're really grateful to have this community celebrate with us and share the joy. So thank you all."