There is a clear runaway winner here, one of the clearest winners I have had in this series of posts; and I fear that my Slovenian friends are not going to be very happy about it. A 1988 novel by a Brazilian writer, mainly set in a mental hosiptal near Ljubljana, it was made into a 2009 film starring Sarah Michelle "Buffy" Gellar (though apparently the film moves the setting to New York, rather than Slovenia, so as not to confuse the audience). I hated the only book I have read by this author, and I see nothing about his Slovenian-set novel that makes me think I want to read it. It is:
Veronika Decides to Die / Veronika Decide Morrer, by Paulo Coelho
Obviously the best-known Slovenian writer is Slavoj Žižek, though he generally writes in English these days, and it's difficult to see how one can argue that any of his his best-known works - The Sublime Object of Ideology, Violence, First as Tragedy, Then as Farce and Welcome to the Desert of the Real - is set in Slovenia.
The top book actually set in Slovenia, by a Slovenian writer, on GoodReads, by a decent margin, is a 2008 novel about young people in Ljubljana whose families fled Bosnia during the war, and the working out of the tensions of the legacy of conflict. It got some unwelcome publicity when the Slovenian police tried to ban it shortly after publication (this collapsed in a welter of publicity which ended the career of the senior policeman concerned). It is:
Southern Scum Go Home / Čefurji raus!, by Goran Vojnović
The top book set in Slovenia by a Slovenian writer on GoodReads (by a very slim margin) is an entirely different affair, a 1984 novel set in Maribor on the eve of the second world war, where a businessman (Maybe Austrian? Maybe not?) stops and makes an assessment of his life and the world. It is:
Northern Lights / Severni sij, by Drago Jančar
But I'm afraid today's prize goes to the Brazilian.