Unlinked titles are out of print, and worth seeking. Many of these are written by clinicians. So does Mosaic Mind by his clinical peer Richard Schwartz. This illustrates that the listings here are a fraction of the available knowledge on splitting and subselves. The below indicates a book that has been significant in shaping my views and this site.
Titles are in alphabetic order.
It is for clinicians and other interested people who want to learn how to apply family-systems principles to chaotic, fragmented inner families of personality subselves. This is out of print, and worth searching for. This illustrates the extreme form of personality splitting in action. Somerville House Books, 1997. Cooper, Mick., and Rowan, John., Eds.