I haven't heard this album in years, but it's unusual in how much pedal Jack McDuff uses on the Hammond organ. No, it's not classical level pedals, but it's unusual to use that much pedal in jazz music. Throughout the album, really. I know there's a 3/4 size doube bassist credited, but if you listen carefully, you can hear the difference.
I don't mean between the string bass and the organ bass — that's obvious — but between the LH Hammond bass plus some attack on the pedal, i.e., "regular" Hammond bass, and how much pedal Jack McDuff was applying, even on mid-tempo swingers. It's a lot of pedal tone, which struck me as unusual. Usually it's not that good a sound for jazz, but this is kind of a lugubrious album, so it works.
And Grant Green is, as usual, exploiting the W-H "dim" (ETA the octatonic symmetrical scale starting with a whole tone interval) scale for his lines, and Yusef Lateef blows a good horn throughout the album.
Not really one of Green's more "relaxed" albums, andt the tension on that set is quite high. Quite possibly because of the tension between having essentially two bassists. I wouldn't know.
It also reminded me I couldn't remember the tune "Old Folks," which I'm glad I was able to play along and remember. You know, some tunes you don't play for years, even simple ones, so it's good to refresh the memory.