A web-based system, method and program product are provided for adding content to a content object stored (e.g., a custom compilation or prepublished work) in a data repository as a group of hierarchically related content entities. Each noncontainer content object is preferably stored as a separate entity in the data repository. Each content entity is also stored as a row in a digital library index class as a collection of attributes and references to related content entities and containers. As the user selects desired objects for inclusion in a content object, the system arranges the objects hierarchically, e.g., into volumes, chapters and sections according to the order specified by the user. The system then creates a file object (e.g., a CBO) defining the content object that contains a list or outline of the container and noncontainer entities selected, their identifiers, order and structure. This file object is stored separately in the data repository. User-provided content is added to the compilation by receiving input content and a target location in the content object from a user, assigning the content an identifier, storing the content in the data repository, and adding its identifier to the list or outline. As an aspect of the invention, a user interface is provided including mechanisms for enabling a user to input the content and specify a target location for the content (e.g., by inserting the title of the user-provided content entity between other entity titles on the outline. Both containers and noncontainers may be added in this fashion.