Harry Kemelman's books featuring Rabbi Small. We've had a few of the series on our shelves for years, but not the whole set of seven. I see that the whole series is available on Kindle at very reasonable prices,which could be dangerous! (In fact there are five more books featuring Rabbi Small, which don't form part of the original series.)
The one I've just re-read, and which I'd pretty much forgotten (except for the bust of Homer and how it came into the story) is Tuesday the Rabbi Saw Red. Rabbi Small seems a meek youngish man, but looks are deceiving. He has an excellent and very sharp brain. He also has a fairly obstreperous congregation of Jewish business people, who slip and slide in their support of him, and who seem more concerned with things of the world than things of the spirit. Although in this book Rabbi Small makes a good case for Judaism being all about care of this world and this in it.
One of the features of these books is that they're not just about an ingeniously crafted murder mystery, though that's always part of the story. It's the way in which we get a picture from the inside of what it means to be a Jew in the modern world (well, the world of the 60s/70s, that is - these books have been around for quite a while now), and how the Jewish mind thinks. This book gives the Rabbi several opportunities for discussion with a class of students, some of whom are Jews, some not, and this allows the reader to see beyond the usual view of what makes a Jew. But the Jewish way of thinking comes through in a number of other more subtle scenes, and through the sharply-drawn characters, major and minor.