Bought the first one as a discarded library book and got completely hooked on the series. The characters are really well worked out and given time to develop. The 'SF' part of the story is subtle, not one of those books that is blinding you with science. Very good story telling with enough detail to make it rich and colourful and so that you can almost taste and smell it. For me the only other SF author that created the same intensity was Ray Bradbury. I really loved the volumes 1 to 4. The 5th one is still good but feels oddly rushed in some parts and drawn out in others.
You need to start with the first one though, or it will be difficult to understand the characters.