Mary Collins has been practicing psychiatry at Harvard University for nearly fifty years. Before that, she was a professional actress and a model. Now, at the age of 83, she has started a new chapter of her professional life, publishing a children’s book earlier this year.

Collins will be available to sign copies of her book -- titled “Lonely Tony”-- at the Bookstall in Marion on Saturday, June 16, from 10 a.m. to 12 p.m. With the Bookstall set to officially close on June 23, Collins’ signing will be the last of many held there over the years.

“Lonely Tony” tells the story of a dog on a quest to find a new friend after his sister, Cleo, passes away. Collins said the book is based on a true story about a friend's dog, and that it’s an uplifting tale about loss, hope, friendship and kindness.

“I had a tear in my eye when I heard the story about Tony and I thought, ‘we have to write this,’” she said. “I think it’s a wonderful story that touches on a lot of things that children ask and wonder about.”

Collins, who’s lived in Marion for more than fifty years, still meets with patients five days a week, and wrote “Lonely Tony” during her spare time.

“It was great fun to write it,” she said. “It really just flowed out of my pen effortlessly.”

The book sold out on Amazon about a month ago, but has since been restocked. Collins said she's also received a lot of positive feedback from kids and parents who have read it.

She said she now plans to continue writing children’s books, and may even write a sequel to “Lonely Tony.”

“A friend’s child called me and said he loved the book and wanted me to write a sequel,” Collins said. “I thought that was wonderful … There’s no way that I’ll stop writing children’s books.”

The secret to maintaining such a workload at her age, Collins said, is her positive attitude.

“I love life and I love psychiatry. I’m really passionate,” she said.

“Lonely Tony” is available on Amazon, and can be bought directly from Collins through mail requests sent to P.O. Box 995, Marion, Ma.