I am a sucker for the Father Brown mysteries.
The style of writing just works for me.
They are entertaining, but also sprinkled with little traces that really make you think, like this one where Father Brown explains:
“A crime is like any other work of art. Don’t look surprised; crimes are by no means the only works of art that come from an infernal workshop. But every work of art, divine or diabolic, has one indispensable mark — I mean that the centre of it is simple, however the entourage may be complicated.”