Nik Bärtsch is a Swiss pianist and composer (click for his Wikipedia entry), and Ronin is a group he formed and which is one of his three main projects. The version of Ronin on this album consists of Bärtsch on piano with other musicians playing bass clarinet, alto sax, bass guitar, drums and percussion. So it's not your typical jazz band lineup, nor is it your typical jazz band music. Self-described as "zen-funk," it incorporates elements of many different musical styles to create something that is certainly jazz but not strictly jazz. I would describe it as hypnotic, funky, mysterious, somewhat in the "chill" range as well as somewhat avant-garde but very listenable.
This is not the kind of thing you would be able to find very easily in any music stores around here, nor do I think you would ever hear of it on the local jazz station (KRTU). Even Amazon.com has only three of his albums available. I got this one from Yourmusic.com, and was surprised to find it there. I do intend to expand my collection of his work with whatever I can find, finances permitting.