Together, Elizabeth G. Macalaster and Pamela D. Greenwood have co-authored several nonfiction picture books using the pen name Ryan Ann Hunter. Their titles are: Into the Sky, Dig a Tunnel, Take Off! and Cross a Bridge.

In writing children’s literature, their goal has been to capture for young people the miracle of the world around us and illuminate our connection to it. The two women met at a writer's group and soon discovered that they shared a sense of wonder about the world of nature, science, and technology. They began to collaborate on nonfiction picture books focusing on these topics.

Pamela lives near Seattle, Elizabeth in New England.