27. A method for using a computer system, in response to a reader's request for display of electronic text, to automatically identify and provide additional reading material related to concepts referred to within said electronic text, comprising: a) via a network, providing to a server system computer instructions that, when executed, formulate a search request for additional reading material related to at least one concept in a text section of an electronic text requested by a client system, wherein said search request includes at least one term that was not provided to said server system by said client system; and b) via a network, providing to said server system, computer instructions for provision to said client system that, when executed on said client system, i) cause said search request to be transmitted via a computer network, resulting in the search of an index, said search resulting in identification of related material; and ii) provide to said client system an indicator of said related material to be presented in the same presentation as the requested electronic text; wherein: said index contains a plurality of terms by which it may be searched: substantially all terms in said index are associated with at least one pointer to a text section; and at least one term in said index is associated with a plurality of pointers, at least two of said plurality of pointers pointing to different text sections.
27. A method for using a computer system, in response to a reader's request for display of electronic text, to automatically identify and provide additional reading material related to concepts referred to within said electronic text, comprising: a) via a network, providing to a server system computer instructions that, when executed, formulate a search request for additional reading material related to at least one concept in a text section of an electronic text requested by a client system, wherein said search request includes at least one term that was not provided to said server system by said client system; and b) via a network, providing to said server system, computer instructions for provision to said client system that, when executed on said client system, i) cause said search request to be transmitted via a computer network, resulting in the search of an index, said search resulting in identification of related material; and ii) provide to said client system an indicator of said related material to be presented in the same presentation as the requested electronic text; wherein: said index contains a plurality of terms by which it may be searched: substantially all terms in said index are associated with at least one pointer to a text section; and at least one term in said index is associated with a plurality of pointers, at least two of said plurality of pointers pointing to different text sections. 28. The method of claim 27 , wherein said additional reading material of step (c) is identified by a computer system other than said server system.