Boundary

Q: "How many books are in the Boundary series?"

"There are four books in the Boundary series, published between 2006 and 2013."

Q: "What is the first book in the Boundary series?"

"The first book in the Boundary series is Boundary, published in 2006."

Q: "What is the Boundary series about?"

"The Boundary series follows scientists who discover evidence of ancient alien civilizations. Starting with Boundary (2006), the four books explore the implications of finding alien artifacts, first on Mars and then in other locations across the solar system. Threshold, Skyspark, and Portal continue the story of human exploration and alien discovery."

Reading order

#	Title	Published	Author	Buy on Amazon
1	Boundary	2006	Ryk E Spoor	Buy
2	Threshold	2010	Ryk E Spoor	Buy
3	Skyspark	2013	Ryk E Spoor	N/A
4	Portal	2013	Ryk E Spoor	Buy

The Boundary series is a hard science fiction collaboration between Ryk E. Spoor and Eric Flint. The first novel, Boundary (2006), begins when a paleontologist finds evidence of aliens in the geological record, leading to a mission to Mars. The series continued with Threshold, Skyspark, and Portal, published between 2010 and 2013.

The four books combine real science with adventure plotting, staying grounded in plausible physics while telling stories about first contact and exploration. The Boundary series also spawned a spinoff, Boundary: Castaway, which follows characters stranded on an alien world.

Frequently Asked Questions

How many books are in the Boundary series?

There are four books in the Boundary series, published between 2006 and 2013.

What is the first book in the Boundary series?

The first book in the Boundary series is Boundary, published in 2006.

What is the Boundary series about?

The Boundary series follows scientists who discover evidence of ancient alien civilizations. Starting with Boundary (2006), the four books explore the implications of finding alien artifacts, first on Mars and then in other locations across the solar system. Threshold, Skyspark, and Portal continue the story of human exploration and alien discovery.

Reading order#

Frequently Asked Questions

Reading order