This is the less commonly heard, second, version of I'm Gonna Leave You. Interestingly, the two versions were released consecutively on Whit 716 and Whit 717.
Both are very good, I just happen to prefer the slightly slower, more country blues sounding, second one. Where the first one rocks, this one lays back and grooves. Doesn't hurt that as a duet [the first is not] the song itself shows much more depth.
Jackie Johnson, the female vocalist and writer of the song [I assume the writing credit given to the owner of the label is BS], is a mystery. I've yet to find a mention of her anywhere. Too bad, as she has such a great voice. I can't imagine a better pairing with Bobby Powell, seems a real shame they didn't do more than this one single together.
[Update: check the comments, one of my readers found Jackie Johnson/Jacqueline Johnson. She's now known as Lady Mem'fis.]