George Mukabi. His career spanned several years before his untimely death in 1963. In that time he only recorded around 30 songs, but they went on to sell hundreds of thousands of copies in his native Kenya and beyond.
This track, Bibi Mama Ngani Mzuri, is simply wonderful. I first heard it on BassClef's excellent mix for Fact Magazine from some time ago which has a host of dizzyingly good African tunes - listen to that here.