Dr. Janina Fisher has many resources on line about IFS/ parts work. I believe it was pioneered by Dr. Schwartz and is a very caring effective therapy acknowledging people are made up not just of one sense of self, but many selves called "parts". The childhood part who is injured, the high functioning part that earns a pay check etc. . Dr. Fisher works with DID and very traumatized people who are fragmented into distinct alters. In other therapy it helps embrace deeply embedded conflicts below consciousness to explore the way in which one part might work against or in concert with other parts, how one part may be I the driver's seat at different moments etc.