Glass Dagger Press
Mark O'Neill

Books by Mark O'Neill

European intelligence units, rogue agencies, deniable missions, and political secrets. Pick a series below and start wherever you like. The books are free to read on Kindle Unlimited.

Department 89

The Reichsbank Gold The Executioner The Traitor Operation Eternal Vengeance Regime Change Operation Thunderbolt Valkyrie Ground Zero Death to Spies The Last Line of Defence

Department 89 Personnel Files

The Survivor The Joker The Avenger The Fixer The Hacker The Enforcer The Jailer The Spymaster

Department 89 Mission Files

Passenger Zero The Stuttgart Syndicate

Edelweiss

Shadowline Oracle Stress Fracture

Jack Maddox

Helix Protocol The Hollow Men The Black Atlas

Ghost Sector

Exit Protocol Exit Vector Exit Line

Self-Publishing Success

Self-Publishing Machine

Frequently Asked Questions

Who is Mark O'Neill?

Mark O'Neill is a British author, based in Germany. The author of 30 books, and more than 20 others under three different aliases, he has become prolific in multiple genres. He specialises in spy and espionage thrillers, as well as writing non-fiction articles on cybersecurity, books, and self-publishing. He also swears a lot and drinks huge amounts of black tea.

Which book series does Mark O'Neill write?

Mark writes in the thriller genre, with series such as Department 89, Ghost Sector, Jack Maddox, and Edelweiss. He also has other series under undisclosed aliases. As of May 2026, he is now also writing non-fiction, with a Self-Publishing Success series.

Are Mark O'Neill's books in Kindle Unlimited?

Yes, all of Mark's books are in Kindle Unlimited. The ebooks are exclusive to Amazon, so unfortunately they can't be found on any other ebook platform.

What languages are Mark O'Neill's books in?

As well as English, Mark's books are also in German, French, and Spanish. As of April 2026, Italian translations are being developed.

Are Mark O'Neill's books in audiobook format?

Mark's books are gradually being converted into audiobooks. The English versions are currently in Amazon's AI-generated audiobook programme, but are restricted to the United States for now. All books in every series are planned for audio, and the Amazon AI-generated editions will eventually be replaced.

Will Mark O'Neill's books be adapted for TV or movies?

A pilot script has been developed for The Reichsbank Gold, with outlines for other books as potential TV series. But there are no imminent plans to produce a TV series or film based on Department 89.

How can I contact Mark O'Neill?

Mark can be contacted by email at mark@markoneill.org. However, if you are a spammer, a Nigerian prince, or a "SEO specialist", don't bother getting in touch.

Does Mark O'Neill have an email newsletter?

Yes, you can sign up for the English thriller newsletter using the Newsletter button at the top of this page. You'll get free books when you sign up, because Mark is nice like that.

In what order should I read the Department 89 books?

Start with The Reichsbank Gold, the first novel in the series, and continue in publication order. While many books work as standalones, the characters and larger story arcs develop across the series.

Which Mark O'Neill series should I start with?

If you like military and intelligence thrillers, start with Department 89.

If you prefer rogue-agent action, try Jack Maddox.

If you like darker conspiratorial espionage, begin with Ghost Sector.

If you want German political-tech thrillers, start with Edelweiss.