In 1991, the Gilmans co-authored Eco-Villages and Sustainable Communities, a seminal study of ecovillages for Gaia Trust.
Another phase of Gilman's life began in the mid 1970s when he decided that "the stars could wait, but the planet couldn't."
He turned his attention to the study of global sustainability, futures research and strategies for positive cultural change.
In 1979 they founded the Context Institute, one of the earliest NGOs to focus on sustainability.
In Context won Utne Reader's Alternative Press Award for "Best Coverage of Emerging Issues" in 1991 and 1994.