Published in 1987, this novel was written in the shadow of the rise of the independent union Solidarity in Poland and the concomitant upsurge of democratic Polish nationalism, and on the cusp of the collapse of European Communism. (I read it as a library checkout a couple of years later, and don't have a copy before me now; but it made a vivid enough impression on me that it's not hard to review it retrospectively, even well over 30 years later.) Poland's culture and circumstances at that time clearly form the model for the unnamed Eastern European country that Moore uses as his fictional setting (and a couple of secondary characters have real-life analogues). Our protagonist is the country's Roman Catholic primate, Stephen Cardinal Bem.
This proved to be a difficult book to classify. For most of the time it's been on my Goodreads shelves, I shelved it as general fiction, perhaps partly because my reading in modern general fiction has been skimpy and could stand to be beefed up :-) , but also because it's mostly a sober-toned, realistic look at important ideas and values (spiritual and moral as much as political), without much violence. (What it has of the latter is important to the plot, however.) It's certainly not action-adventure. But in considering it preparatory to writing this review, I moved it to the "espionage" shelf. True, none of the characters are actually spies as such. But the premise of the book, and the events of the plot, revolve very much around covert plotting and intrigue, with very high political and even geopolitical stakes --and a very real danger of a large-scale bloodbath if things turn out wrongly.
At about 182 pages, and written with a crisp and straightforward style, this was a quick read that engrossed my attention throughout, and kept me turning pages. For much of the book, exactly what's really going on is murky for the cardinal (and for the readers, since he's our viewpoint character). But the element of mystery adds to the appeal (and the murk will be dispelled). By the time he wrote this book, Moore (1921-1999) was a veteran author with many novels under his belt, and his seasoned craftsmanship shows; his prose is well written and his characterizations sharp. (Stephen is the best drawn.) There's no sexual content, and relatively little bad language. (The f-word appears only once, spoken by a minor character; although it's of German derivation, that isn't necessarily incongruous for a Slavic speaker, since some Slavic languages have an equivalent.)
Though the Irish-born Moore professed to have lost his religious faith as a young man, he was raised as a Catholic and his novels apparently very often grapple with questions of religious faith and its relation to life (though this is the only example of his work that I've read). Given the protagonist's calling, readers can guess going in that the viewpoint here will be religious. And indeed, the strength of this novel is very much the quality of its reflection on the question of how Christian believers, ruled by an authoritarian government that's hostile to their faith and leaves a lot to be desired in moral and public-policy terms, should conduct themselves, as both members of a national community and as subjects of the Prince of Peace. Seen through the eyes of a devout Christian who's thoughtful, humble, and self-critical, the answers aren't glib or facile. Despite Stephen's church affiliation, they also aren't particularly "Catholic" in a parochial denominational sense; Christians of any communion can relate to and identify with him, and profit from the message that Moore, in spite of his lapsed state, presents sympathetically here.
During his lifetime, Moore enjoyed a great deal of success and even critical recognition for his fiction (this novel was actually a serious contender for the UK's Booker Prize). But as he demonstrates here, he could also appeal to ordinary readers who appreciate solid, serious fiction crafted in the great tradition of genuinely good literature. I wouldn't hesitate to recommend this book to any one of those readers (with the caveat that if you necessarily have to have a feel-good ending to your fiction, you're not guaranteed that here!).