When the Earth Was Green: Plants, Animals and Evolution’s Greatest Romance
By Riley Black
St. Martin’s Press, 2025

Stories of prehistory usually focus on animals, but it was the plants and their ability to adapt to an evolving planet that made animal life possible. When the Earth Was Green walks through prehistoric time and place to explore the influence of plants on animal evolution and vice versa. Black shows how the dinosaurs of the Mesozoic era, the colossal mammals of the Ice Age, and even modern-day humans would not exist without the evolutionary efforts of their green counterparts, underscoring how the interactions between species have shaped the planet we call home.

This event is presented in partnership with The Nature Generation. 

About the Author
Riley Black is a paleontologist and science writer. She won the 2023 AAAS/Subaru Prize for Excellence in Science Books as well as the National Center for Science and Education’s 2024 Friend of Darwin Award. Her books include Skeleton Keys and The Last Days of the Dinosaurs. Riley recently moved to Maryland from Utah.

Purchase the book
Please help support local independent bookstores by purchasing this book at Browseabout Books, official bookseller of the History Book Festival. Online sources and digital versions are tempting; however, supporting local brick and mortar shops helps to preserve our vibrant main streets. Drop by Browseabout, order books online, or call the store at 302-226-2665. You also may purchase a copy at biblion in Lewes.

About the Festival
The History Book Festival is the first and only book festival in the United States devoted exclusively to history. With the help of our presenting funding partners — Delaware Humanities and The Lee Ann Wilkinson Group, Berkshire Hathaway HomeServices | PenFed Realty — as well as our program and community partners, volunteers, and donors, the 2025 History Book Festival will be full of great discussions with authors of newly published narrative nonfiction and historical fiction. 

Thanks to all of our donors, especially our education and outreach funding partners: Ronald Collins & Susan Cohen, Carolyn & Aaron Nayer, Jen Mason & Clare Hancock, and Browseabout Books. HBF authors visit classrooms in Delaware, and HBF provides their books to schools, libraries, and community organizations.

Our Keynote event is presented by Griswold Home Care for Sussex and Kent Counties and Sally Mott Freeman & John K. Freeman; our Closing event is presented by the Delaware Community Foundation. Saturday’s Spirited Discussion, our gathering for attendees and presenters to celebrate and discuss their day, is presented by Dogfish Head Beer & Benevolence.

Special thanks to our Founding Program Partners for their continuing support: the Lewes Public Library, for event promotion and production, and Browseabout Books in Rehoboth Beach, official bookseller of the History Book Festival. Thanks also to the  Lewes Chamber of Commerce for event promotion, and the Cape Gazette and Delmarva Public Media, our media partners.