Skip to Main Content

Threshold

Part of Boundary

The second book in the popular Boundary SF adventure series co-authored by multiple New York Times bestseller Eric Flint and Ryk E. Spoor. 

When the strange fossil she'd discovered gave her a trip to Mars, Helen Sutter thought she'd gone about as far as any paleontologist would ever go in her lifetime. But when you’re married to an overconfident super-sensor expert for the only private agency in space – the Ares Corporation – and your best friend is a former secret agent for the Interplanetary Research Institute of the United Nations, there's always somewhere farther to go. 

Soon Helen’s new discoveries will lead her  to the mysterious asteroid Ceres and beyond in a desperate race to reach Jupiter's perilous miniature system of radiation-bombarded moons. It seems the next gold rush is on–for alien technology.   

And there are people willing to do anything to get it – even if they must start the Solar System’s first interplanetary war!

Praise for the Boundary series:
“A genial, fast-paced sci-fi espionage thriller [that is] light in tone and hard on science…” –Publishers Weekly on Threshold

Eric Flint is a modern master of alternate history fiction, with more than three million books in print. He’s the author/creator of the multiple New York Times best-selling Ring of Fire series, starting with first novel 1632. With David Drake, he has written six popular novels in the “Belisarius” alternate Roman history series, and with David Weber, he has collaborated on 1633 and 1634: The Baltic War and latest Honorverse series entry Cauldron of Ghosts. Flint's latest Ring of Fire novel is 1637: The Polish Maelstrom. Flint was for many years a labor union activist. He lives near Chicago, Illinois.

More books in this series: Boundary