Various embodiments of the present invention include a grazing routine that selects data objects from a data-object library or database based on selection-criterion values associated with each data object and provides the data objects to a presentation routine that uses the data objects to continuously update a data-object presentation. User input directs subsequent data-object selection by the grazing routine to allow users to intuitively navigate and search a large data-object library in order to locate one or a set of particular data objects. Users can input selection commands to specific presented data-objects in order to focus subsequent data-object selection and data-object presentation to increasingly smaller sub-populations of data objects. In the absence of user input, the sub-population of data objects from which data objects are selected for presentation may be increased.