A data structure and method are provided for storing a content object stored (e.g., a custom compilation or prepublished work) as a group of hierarchically related content entities Each content entity is contained in a separate file object. An attribute file object corresponding to each content entity file object contains attributes pertaining to that entity. A list or outline containing container and noncontainer identifiers defines the content, order and structure of the content object. This list or outline is stored as a separate file object (e.g., a CBO or the PSF file of a prepublished work).