I agree with the above posters but also look at Isaac Hayes. Black Moses, Movement, To Be Continued and Hot Buttered Soul are all classic albums.
It's a Soul Thang
My son and I have been on a now extended Soul music kick. Late 60's-mid 70's stuff, after some of the artists evolved from pop, before a lot of artists turned to disco, and way before what is now consider R&B. You know, Al Green, Aretha, Stevie, Gaye, Withers, Billy Paul, Mayfield, Temptations, Spinners..etc. Looking for some of the perhaps less obvious choices that folks enjoy that they'd like to suggest for fleshing out and expanding our collections! Thanks.