The Idaho mom who wrote a widely read essay about her worries concerning her mentally ill son in the wake of the Sandy Hook Elementary School shootings has signed a deal to write a book about her issues with the mental health-care system.

Liza Long, who wrote the essay “I am Adam Lanza’s mother,” is writing a book titled, “I Am Michael’s Mother,’’ a spokesperson for publisher Hudson Street Press confirmed to TODAY.com on Thursday. The book will be about the poor state of the mental health-care system and Long’s struggles with it while raising a bright but mentally ill child as a single mother.

'I Am Adam Lanza's Mother': Another mom's cry for help

“Every time I hear about a mass shooting, I think about my son,’’ Long told NBC News in December. “And I wonder if someday, I’ll be that mom.’’

Long’s essay was first published on her own mom blog only days after Lanza shot and killed 20 children and six adults at Sandy Hook Elementary School in Newtown, Conn., in December 2012. Another of Lanza's victims was his mother, Nancy Lanza. Long expressed similar fears about her 13-year-old son in her essay.

“I live with a son who is mentally ill,’’ she wrote. “I love my son. But he terrifies me.

“I am sharing this story because I am Adam Lanza’s mother. I am Dylan Klebold’s and Eric Harris’s mother. I am James Holmes’s mother. I am Jared Loughner’s mother. I am Seung-Hui Cho’s mother. And these boys — and their mothers — need help. In the wake of another horrific national tragedy, it’s easy to talk about guns. But it’s time to talk about mental illness.”