Abstract: A system and methods for utilizing advanced automated search techniques including highlighting capability for determining subsets of relevant content data (in paper or electronic form) is disclosed. These techniques are advantageous in reviewing vast collections of content data or documents to identify relevant data or documents from the collections. The advanced search techniques are based on query terms, which isolate relevant content data that respond to the query terms. A probability of relevancy can be determined for a unit of content data or document in the returned subset to facilitate exclusion of a document from the subset if it does not reach a threshold probability of relevancy. Documents in a thread of a correspondence (for example, an e-mail) in the responsive documents subset can be added to the responsive documents subset. Further, an attachment to a document in the responsive documents subset can be added to the responsive documents subset.