We describe in this paper the Internet Fish Construction Kit, a tool for building persistent, personal, dynamic information gatherers (“Internet Fish”) [3] for the World-Wide Web. Internet Fish ( IFish) differ from current resource discovery tools in that they are introspective, incorporating deep structural knowledge of the organization and services of the Web, and are also capable of on-the-fly reconfiguration, modification and expansion. Introspection lets IFish examine their own information-gathering processes and identify successful resource discovery techniques while they operate; IFish automatically remember not only what information has been uncovered but also how that information was derived. Dynamic reconfiguration and expansion permits IFish to be modified to take advantage of new information sources or analysis techniques, or to model changes in the user's interests, as they wander the Web. Together, these properties define a much more powerful class of resource discovery tools than previously available. The IFish Construction Kit makes it possible to rapidly and easily build IFish-class tools. The Kit includes a general architecture for individual IFish, a language for specifying IFish information objects, and an operating environment for running individual IFish.