1. A method of presenting information stored on computer readable media on at least one display device with the aid of at least one computer and an input device for selecting information displayed on the at least one display device, comprising, in a presentation session: the at least one computer causing the at least one display device to display thereon, from information stored in the computer readable media, a first plurality of selectable items from a first index that comprises a plurality of levels, at least one of the selectable items in the first plurality being from a different level of the index from at least one other of the selectable items in the first plurality, and, concurrently therewith, at least one selectable item in the first index not included in the first plurality of selectable items or in a second index; in response to receiving via the input device selection of an item of the first plurality of selectable items, the at least one computer causing the at least one display device to display information related to the selected item of the first plurality of items concurrently with display of the first plurality of items and the at one least selectable item; and in response to receiving via the input device selection of the at least one selectable item, the at least one computer causing the at least one display device to display, in place of the first plurality of selectable items, a second plurality of selectable items, in the first index or in the second index, that is at least partially different from the first plurality of selectable items concurrently with display of at least one other selectable item that was previously selected in the presentation session; wherein the first plurality of selectable items is displayed in a group such that it is visually apparent which selectable items are in the first plurality of selectable items and which selectable items are not, the first plurality of selectable items comprising all of the selectable items that are displayed in the group; wherein the first plurality of selectable items is displayed in a manner that indicates the relative levels of the respective selectable items in the first plurality of selectable items; wherein causing the at least one display device to display information related to the selected item of the first plurality of items comprises causing the at least one display device to display in association with the information displayed related to the selected item of the first plurality of items a source or sources of the information displayed, each source being a database or a publisher, and an indicator associated with each displayed source indicating a number of items of information of a respective source related to the selected item; and wherein, in response to receiving the selection of an item of the first plurality of selectable items, the computer system neither adds any selectable items to the display of the first plurality of selectable items nor removes any selectable items from the display of the first plurality of selectable items.