Embodiments of the present invention enable users to generate a summary for a document with respect to a concept, making use of inherent hierarchies present in a text document based on subject-object relationships of the sentences in the text document. In one embodiment, a text document is parsed into sentences, and a tuple is created for each sentence, the tuple comprising a subject and an object found in the sentence. The tuples may then be searched for a specified topic to identify matching tuples, as well as tuples that are related to the matching tuples based on relationships between their respective subjects and objects. A summary focused on the specified topic may then be generated using the sentences corresponding to the matching tuples and the tuples related to the matching tuples.