JH Gruger
Award-Winning Hard Science Fiction Author
The Sentinel Suppressions Series
VOX PROXIMA PRESS
JH Gruger is the award-winning author of the hard science fiction thriller series, The Sentinel Suppressions. Set in the near future, the sci-fi techno-thrillers follow humanity’s desperate defense against an alien invasion by the Sentinels, who must prevent human advancements that could threaten the galactic order.
Book Two of The Sentinel Suppressions, Tyrants of Gravity, follows humanity’s desperate defense against the alien Sentinels. Scott Anderson defeated the aliens using human scientific, technological, and telepathic advancements. Mankind now stands on the threshold of interstellar space travel with black-hole-powered propulsion technology and planet-killing weaponry, violating the galactic nonproliferation laws.
The wreckage of the alien space battleship drifts in Earth’s orbit. But mankind is unaware that an insidious alien AI remains, infecting social networks and provoking eugenics hatred to exterminate neurodivergent telepathic humans.
The relative peace on Earth is shattered by an approaching extraterrestrial fleet that prepares to launch planet-killers. Scott and his autistic-telepath brother Robby have little time to recognize the threat and develop weapons that counter the advanced technologies and eugenics threat of the Centauran fleet. If they fail, human civilization will be destroyed, and billions will die. The neurodiverse humans hold the keys to survival.
What readers are saying:
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"For readers who want their science fiction to argue, bruise, and burn. Tyrants of Gravity is a sci-fi novel that thinks big and hits with surprising heart." - Literary Titan
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"brilliant . . . A standout work for fans of sci-fi. It invokes the awe of interstellar while maintaining the gritty grounded tension"
What if the greatest danger to humanity wasn’t on Earth — but from alien sentinels watching from space?
In Book One, Gravity of Sol-3, Scott Anderson wants two things: to keep his family alive and to lose himself in the elegant beauty of physics. But the world won’t let him have either. Fascist thugs hunt his neurodivergent family. Eugenicist gatekeepers have corrupted the scientific institutions he hoped would be his sanctuary.
And now, as humanity’s brightest minds edge closer to cracking the secrets of black hole technology, something far more powerful than any earthly enemy has taken notice — alien sentinels in orbit, ancient and impassive, have already decided the penalty for humanity’s ambition. The Sentinels attack with black-hole-powered kinetic weapons and with an insidious extermination of neurodiverse humans. Scott and his autistic brother are running out of places to hide.
Scott’s only hope of survival is to press forward to transform his black hole technology into a weapon of defense.
What readers are saying:
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“Arthur C. Clarke would have enjoyed this!”
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"such a fun and captivating read"
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"Excellent, well-paced, believable storyline. If I could give this 6 stars, I would"
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"A tense, cerebral tale of rebellion and resilience set in a near-future Earth controlled by alien Sentinels. . . one of the most chilling antagonists I've encountered in recent science fiction."
NEWS & REVIEWS
Reviews for Tyrants of Gravity:
April 2026 "...for readers who want their science fiction to argue, bruise, and burn. Tyrants of Gravity is a sci-fi novel that thinks big and hits with surprising heart."
January 2026 "Lovers of sci-fi novels blended with adventure, suspense, and action will find Tyrants of Gravity by JH Gruger an enthralling read."
Reviews for Gravity of Sol-3:
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Literary Titan Silver Book Award:
Fiction - Science Fiction genre
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Five Star Review for Gravity of Sol-3 by Readers' Favorite November 2024
"A tense, cerebral tale of rebellion and resilience set in a near-future Earth controlled by alien Sentinels. . . one of the most chilling antagonists I've encountered in recent science fiction."
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Editorial Book Review December 2024
"Engineering New Worlds: How JH Gruger Fuses Science & Storytelling in His Sci-Fi Series"
About the Author
Hard science fiction from JH Gruger. “For readers who want their science fiction to argue, bruise, and burn … that thinks big and hits with surprising heart.”—from Literary Titan’s 5-star review.
