There’s nothing quite listening in on a smart conversation by two old friends. In this week’s Boston Phoenix, Catherine Tumber talks with Jon Garelick about her new book, “Small, Gritty and Green: The Promise of America’s Smaller Industrial Cities in a Low-Carbon World.”

Cathy’s big idea is that down-on-their-luck cities like Lowell and Springfield may be due for a revival as economic and environmental constraints make urban living more appealing. And unlike major metropolises such as New York or Los Angeles — or Boston, for that matter — small cities have the capacity to develop their own self-sufficient ecosystems, including locally grown food.

The book is based on an essay Tumber wrote for the Boston Review in 2009 titled “Small, Green and Good.”

I read “Small, Gritty and Green” in galleys last spring, and I recommend it highly. Cathy also has given me invaluable advice for my own book-in-progress on the New Haven Independent and other community news sites, tentatively titled “The Wired City.”