Division One Books in Order
Part ofStephanie Osborn Books in OrderFind the Division One series by Stephanie Osborn in order, with summaries, series background, and a simple guide to starting this secret-agency science-fiction saga.
Last updated: July 14, 2026
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Division One books in publication order
14 books
A Small Medium At Large
by Stephanie Osborn
2017
A rebel faction wants a mysterious device once carried to Earth by a man known to humans as Harry Houdini. Echo and Omega must learn what the F'al is and why its return could restart an old conflict.
A Very UnCONventional Christmas
by Stephanie Osborn
2017
Christmas brings trouble to Division One when signs point to a mole inside the Agency. Echo and Omega must protect their team while uncovering who is leaking dangerous information.
Alpha and Omega
by Stephanie Osborn
2017
NASA astronaut and astronomer Megan McAllister meets Division One agent Echo in West Texas and is recruited into a world of hidden threats. He soon learns that his new partner, Omega, is more unusual than anyone expected.
Tour de Force
by Stephanie Osborn
2017
Alpha One takes on a mission where nothing is quite what it first appears. Echo and Omega must separate deception from fact before hidden motives put the team and their larger mission at risk.
Definition and Alignment
by Stephanie Osborn
2018
A new enhanced human reveals that an old enemy's plans are not over. Alpha One becomes the target of a telepathically driven manhunt that can follow Echo and Omega almost anywhere.
Phantoms
by Stephanie Osborn
2018
Echo and Omega try to make room for an ordinary date, but Division One business refuses to stay away. Their evening collides with a new threat that forces the team back into action.
Texas Rangers
by Stephanie Osborn
2018
Echo and Omega return to Earth for another Division One case with danger close to home. The mission brings covert work, unusual threats, and pressure on the partnership at the heart of Alpha One.
Trojan Horse
by Stephanie Osborn
2018
A training flight turns into a space battle when the Cortians target Alpha One. Echo and Omega crash on a primitive world, injured and hunted, while their team fights to reach them.
Break, Break, Houston
by Stephanie Osborn
2019
Division One faces another high-risk operation where communication, timing, and teamwork matter as much as firepower. Echo and Omega must keep their people together while a dangerous situation escalates.
Head Games
by Stephanie Osborn
2019
While Alpha One faces a horrifying crisis, assassins target the president of the Galactic Coalition. A difficult first-contact mission and growing political strain leave Echo and Omega caught between duty and danger.
Tourist Trap
by Stephanie Osborn
2019
Echo and Omega take a much-needed vacation on the Eden-like world of Tiniken, only to cross paths with a Cortian slave ring. When Echo is recognized, relaxation becomes a rescue mission.
Mega Moth
by Stephanie Osborn
2020
Something is attacking Manhattan while Echo struggles to recover from earlier injuries and Omega deals with trauma of her own. Alpha One must confront the new danger before the city pays the price.
Byegones
by Stephanie Osborn
2021
Echo and Omega explore whether Omega can safely have a child, even as their work with Division One continues. The personal question becomes another source of pressure in a life already shaped by dangerous missions.
The Bounty Game
by Stephanie Osborn
2021
An imposing alien woman makes a claim that challenges Agent Omega's understanding of what is possible. The revelation draws Alpha One into another dangerous problem with stakes that reach beyond routine Agency work.
Division One books in chronological order

Alpha and Omega
by Stephanie Osborn
2017Division One, Book 1
A Small Medium At Large
by Stephanie Osborn
2017Division One, Book 2
A Very UnCONventional Christmas
by Stephanie Osborn
2017Division One, Book 3
Tour de Force
by Stephanie Osborn
2017Division One, Book 4
Trojan Horse
by Stephanie Osborn
2018Division One, Book 5
Texas Rangers
by Stephanie Osborn
2018Division One, Book 6
Definition and Alignment
by Stephanie Osborn
2018Division One, Book 7
Phantoms
by Stephanie Osborn
2018Division One, Book 8
Head Games
by Stephanie Osborn
2019Division One, Book 9
Break, Break, Houston
by Stephanie Osborn
2019Division One, Book 10
Tourist Trap
by Stephanie Osborn
2019Division One, Book 11
Mega Moth
by Stephanie Osborn
2020Division One, Book 12
Byegones
by Stephanie Osborn
2021Division One, Book 13
The Bounty Game
by Stephanie Osborn
2021Division One, Book 14
Series background & context
Division One is Stephanie Osborn's secret-agency science-fiction series about the people called in when an event is too strange, too dangerous, or too embarrassing for the ordinary world to see. The starting point is Dr. Megan McAllister, a NASA astronaut, astronomer, and polymath whose already unusual life changes when she meets a man in black in West Texas.
That man is Agent Echo. He recruits Megan into Division One, an organization that deals with threats at the edges of human knowledge. Megan becomes Alpha One, also called Omega, and discovers that she is more than Echo first realizes. Their partnership, both professional and personal, becomes the series' center.
The early books establish the mix: covert operations, unexplained visitors, advanced technology, and missions that can quickly move beyond Earth. A Small Medium At Large brings a strange device and the legacy of Harry Houdini into the team's orbit. A Very UnCONventional Christmas places a mole inside the Agency, while Tour de Force makes clear that appearances are rarely the whole story.
Then the series goes bigger.
In Trojan Horse, Echo and Omega are stranded after a space battle and must survive while their enemies search for them. Later books introduce rival powers, political pressure, espionage, and the ongoing danger posed by the Cortians. The team faces threats in cities, on alien worlds, and in the spaces between them.
The action is fast, but the characters are not interchangeable operatives. Echo and Omega have to navigate trust, recovery, leadership, loyalty, and the cost of continually being sent into danger. Supporting members of Alpha Line matter, too, especially as the scope of the conflicts grows.
This is a wide-ranging series with a pulpy, team-adventure feel. It has secret files, alien politics, chases, starships, and battles, but it also keeps returning to the question of what a person owes their partner, their team, and the people they are trying to protect.
Begin with Alpha and Omega. The books build on earlier missions and relationships, so reading in order gives the clearest view of Omega's development and the evolving world around Division One.
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