A review of research reveals that, although several reading researchers recognize the significance of grammatical complexity beyond the sentence in reading comprehension, little research exists in this area of grammatical interrelationships among sentences. The first step toward an understanding of grammatical complexity beyond the sentence is for reading researchers to specify elements within this linguistic phenomenon so that formalized rules can be established to govern the text-forming process. M. A. K. Halliday and Ruqaiya Hasan have provided such a first step with their explanation of cohesion, the relations in meaning that are achieved by references of certain lexical and grammatical elements to other elements across the sentences in discourse. Additionally, there is a need to determine how skilled writers use cohesive features in prose of various aims and modes. With further identification of models of performance, future research can determine how cohesive features affect first and second language speakers' comprehension of English, the differences in comprehension that occur for implicitly and explicitly stated content, and how attention to cohesive features can be used to measure readability. (RL)