Watch the The Forgotten Finger online guitar lesson by Paul Brown from Smooth Jazz Handbook
The thumb, the forgotten finger. A lot of people compare my stuff to Wes Montgomery who is really well known for using his thumb. Picks were around and he had access to picks as we all do but there's something in the sound of playing with your thumb that's very earthy and warm. In developing the sound with the thumb, the sound that's generated with the guitar is very warm and soothing.