Like the person identity on the personal, racial, cutural, ethnic and gender level. Here is some insight:
Personal: human caracteristics
Gender: Role in society
Racial: Geographic situations
Cultural: tribalism, groups
Ethinicity: change of society
Its cool how they all relate and differ from each other. You can explore the social and personal thought just by been born in diffrent places. The subject is very broad but the subject is well known.
I suggest "In the Name of Identity:Violence and the Need to Belong" by Amin Maloof. He explores how identity affects us deep down in our souls...quite in intresting subject!