The Laundry Files series
by Charles Stross
The Atrocity Archives (2004)
The Jennifer Morgue (2006)
The Fuller Memorandum (2010)
The Apocalypse Codex (2012)
The Rhesus Chart (2014)
The Annihilation Score (2015)
The Nightmare Stacks (2016)
The Delirium Brief (2017)
The Labyrinth Index (to be published 2018)
It’s a mixed blessing for a fan of an author when that author has a really good series of stories that happens to be rather open-ended. There’s always the chance for another entry in the series, but you feel compelled to read them all. And there’s the problem that the stories might have a specific order in which they should be read. Miss one, and you lose a lot of background information in the next. Or the author has to keep adding annoying infodumps to fill the reader in.
With his “Laundry Files” stories (the above-mentioned novels, plus a handful of shorter works), Stross has managed to avoid those problems for the most part. While the order given is both the order of publication and the order in which the stories take place, they can be read and enjoyed separately. A couple of the later entries (Score, Stacks, Index) even center on side characters.
Speaking of which, the main character is Bob Howard, an office flunky in Britain’s secret government agency that deals with the “occult”. Thanks to being in the right place at the right time (though to Bob, it’s the wrong place and wrong time), he rises quickly through the ranks to become the de facto head of the agency.