We propose a two-component theory of text signaling devices. The first component is a text-based analysis that characterizes any signaling device along four dimensions: (a) the type of information it makes available, (b) its scope, (c) how it is realized in the text, and (d) its location with respect to the content it cues. The second component is a reader-based analysis in which signaling effects on text-processing are hypothesized to depend jointly on (a) the relevance of the signaled information to the readers' goals and background knowledge and (b) the accessibility of the signaled information to cognitive processes. The two components of the model are closely related: The text-based component specifies the information made available to the reader, and the accessibility of that information is influenced by the realization properties, scope, and location of the signaling device relative to the cued content. (Contains 2 tables and 3 figures)