This paper introduces the DReSDeN¹ tutorial dialogue manager, which adopts a similar Issues Under Negotiation approach to that presented in Larsson [20]. Thus, the information state that is maintained in DReSDeN represents the items that are currently being discussed as well as their inter-relationships. This representation provides a structure for organizing the representation for the interwoven conversational threads [26] out of which the negotiation dialogue is composed. We are developing DReSDeN in the context of the CycleTalk tutorial dialogue system that supports the development of critical thinking and argumentation skills by engaging students in negotiation dialogues. We describe the role of DReSDeN in the CycleTalk tutorial dialogue system, currently under development. We then give a detailed description of DReSDeNs underlying algorithms and data structures, illustrated with a working example. We conclude with some early work in using machine learning techniques to adapt DReSDeNs behavior.