Being that something like 85% of people diagnosed with a dissociative disorder are also diagnosed with PTSD, these two disorders are closely related. Two books that i have found that discuss this relationship and the various diagnosis of dissociative disorders are "The Stranger in the Mirror", written by the woman who helped to develop the SCID-D, which is the primary tool to diagnosis dissociation. The other is "Rebuilding Shattered Lives: Treating Complex PTSD and Dissociative Disorders" by James Chu a doctor who has treated dissociative and trauma patients at McClean Hospital in Boston. This is one of the premier hospitals for trauma disorders in the United States. I have been diagnosed with DID, but these two books have been very helpful in understanding all the different types of dissociation I do experience.