1. A method for dynamically obtaining a unified classification information graph (UCIG), the UCIG providing a navigation system for a user to access sought information, the method comprising the steps of: (a) providing a plurality of information resources not all necessarily having the same conceptualization system, each resource including a respective hierarchy of categories, leaf categories in each hierarchy being connected to information pages; and (b) generating a UGIC by carrying out knowledge acquisition tasks using at least the hierarchy of categories and the categories of the information resources, the UCIG including a unified hierarchy of categories, leaf categories in the unified hierarchy of categories being connected to information pages of the plurality of information resources, such that information pages accessible through the hierarchy of the plurality of information resources are also accessible through the unified hierarchy of categories of the UCIG.