Margins
Secrets of Mars book cover 1
Secrets of Mars book cover 2
Secrets of Mars book cover 3
Secrets of Mars
Series · 3 books · 2021

Books in series

The Fossil book cover
#1

The Fossil

2021

A human fossil on Mars. An astronaut who lost her memory and a powerful organization that keeps a secret in Antarctica—one that will change the world forever. In 2018, Canadian archaeologist Ron Jackson makes a mind-boggling discovery in Antarctica—right before disappearing without a trace, leaving behind only his controversial theory that humans have lived on Earth far, far longer than we think they have. Decades later, in 2042, when Jackson's wife dies under mysterious circumstances, an unlikely pair of investigators, Agatha Devenworth and Pano Hofer, begin investigating whether her death might be connected to Jackson's disappearance. What exactly was it he found before he vanished? Why is the Human Foundation, a hyper-powerful business empire built on an endless series of game-changing inventions it has been rolling out, one after another, for over twenty years, trying to hide the truth from the two investigators? And what could it possibly have to do with the first manned mission to Mars, which ended in disaster leaving countless conspiracy theories in its wake?
The Fossil 2 book cover
#2

The Fossil 2

2021

For years, Filio Amorosa has had one goal, and only one goal: getting back to Mars. All that matters is finding out what happened on her mission there, and why she can’t remember any of it. But when she finally discovers the truth, it blows her whole world apart. Meanwhile, on Earth, Agatha Devenworth and Pano Hofer have a new mission: travel from the Human Foundation’s secret underground base to New York to uncover what the enemy is plotting. Can they find a way forward for humanity in the midst of this clash of otherworldly forces?
The Fossil 3 book cover
#3

The Fossil 3

2021

t’s been twenty years since the first manned mission to Mars discovered a human fossil on the Red Planet. Now, the democracies of the West are buckling under a new crisis emerging from Russia: ten thousand liberated Builders, now fully grown and no longer protected by the UN, are forced to flee. One country is ready to receive the descendants of Xinth: the Special Administrative Region of South Africa, where a lone Builder, Hortat, is running for president. The situation is unprecedented, and around the world is giving rise to as much distress as it is hope for a better future for humanity. Hortat wins, but is mysteriously assassinated on election night. To unravel the mystery, head of the Human Foundation Luther Karlhammer calls in a familiar face: former investigator Pano Hofer. He’s long since walked away from his old life as an investigator, but another name from the past, Agatha Devenworth, lures him out and draws him into a deadly plot ...

Author

Joshua T. Calvert
Joshua T. Calvert
Author · 33 books

Joshua T. Calvert has traveled the world—on foot, by Jeep, by bicycle, by motorcycle, and lots of other ways besides. As you might imagine, he's seen many things most people never see - including an Iranian prison cell, from the inside! In Kyrgyzstan, he fared slightly better, narrowly avoiding being kidnapped for ransom. Skydiver, scuba diver, martial artist, adventurer - his goal is to experience everything possible, and then make it real to you in his books. And he's made a good run of it so far: in the Philippines, he did police training on multiple types of firearms (despite being no fan of guns himself); dove in Asian waters among sharks and shipwrecks; and patrolled with Sumatran jungle rangers. That's what defines Calvert's approach to method writing: pushing himself beyond his own limits, to experience first-hand what his characters experience, to make your immersion in his stories as deep as it can be. For Ganymede Rises, after a slight detour with some smugglers in the deserts of Uzbekistan and the steppes of Mongolia, he traveled by dogsled and snowshoe to the Arctic Circle to experience first-hand what it's like to be utterly isolated in the coldest place on Earth. For his book The Fossil, he sat with professional pilots in flight simulators for Airbus A320 and Boeing 737 aircraft to learn what it's like to fly a passenger jet. His latest adventure: a parabolic flight with European Space Agency astronauts, to experience zero-gravity. All so he can describe it to you, in his own words.

548 Market St PMB 65688, San Francisco California 94104-5401 USA
© 2025 Paratext Inc. All rights reserved