During the last 20 years, there has been an enormous amount of research examining sources of coherence in reading. A major tenet of this work has been the distinction between two major sources of coherence. "Text-based" sources of coherence are contained within the text itself -- use of headings to indicate aspects of a text's macrostructure; "reader-based" sources of coherence encompass the information and strategies that the reader brings to the comprehension process. Many early models of reading comprehension emphasized text-based sources of coherence as a way of understanding how a representation of the text is constructed in memory. However, during the last decade, there has been a clear shift of theoretical perspective away from viewing reading comprehension as a process of representing a text to viewing comprehension as a process of representing what a text is about. This has led to a greater emphasis on reader-based sources of coherence. The purpose of this book is to bring together the large body of evidence addressing the roles of text-based and reader-based sources of coherence in reading comprehension. The contributors present the current state of cognitive theory and research on comprehension of discourse.