You could fill a mansion with both rock and soul records by people that put an album out, and sank into obscurity. The differance is, in soul, you really had to be good--at singing or playing- to even get onto wax. The music demands a good voice, and the ability to lock into syncopated rythms. It would be fun to find out exactly why Aretha Franklin became an international superstar, while people just as good remain unknown.
Marlena Shaw is a case and point: She has a great voice, the ability to sing sweet soul, grittiy southern soul, and jazz. For a soul album, this is very, very diverse, and everything works. Shaw even does some out and out scatting on this--not easy to do--and is a master.
There are all kinds of music and textures on here. All are done beatifully. There is even a version of Calafornia Soul that puts the 5Ds cover to shame and I like the 5ds version.
Obviously, as with most soul records, this is not a revelation, but that is rare in this type of music, because it is a narrow construct. But if you like soul and R&B, this is an essential album, just because it is SO good.