Wepresent a new computer tool for modeling inference generation processes in text comprehension, Withthis tool, an explicit inference statement is constructed by marker passing in ajoint text and knowledge base and a subsequent compilation process, In addition, the tool can be applied to describe knowledge integration processes, which can produce spatial, causal, and other types of representations. Because the system provides explicit accounts for reproductive and creative inferencing, it exceeds the functionality of previous simulations in text research. Text researchers can employthis system as a common ground for comparing their different positions on inferencing in a more precise manner.Within the last decade, inference generation has become one of the most central research topics in the area on text comprehension (Graesser, Singer, & Trabasso, 1994;McKoon & Ratcliff, 1992). Previous research on text comprehension has been greatly advanced by the development and application ofcomputer simulation tools that have enabled researchers to more precisely specify the assumed cognitive representations and to subsequently simulate the postulated cognitive processes on a computer. For example, Turner (1987) has developed a computer tool, the propositional analysis system, which allows researchers to apply Kintsch's (1974) theory of language comprehension in a precise and more efficient manner. With this system, written information can be interactively transformed into a set ofpropositions that embody its meaning. Kieras (1991) has similarly developed a widget that parses simple texts into its propositions. Miller and Kintsch (1980) and Mross and Roberts (1990) have written computer programs that simulate how coherent text and situation representations are formed from propositions and other knowledge units. Such computer tools have been widely applied and have significantly