This research explored the fundamental processes involved in comprehending linguistic material: the duration of the process, the sequence of processes, and the sources of errors. One project examined the comprehension of affirmative and negative sentences that are read and verified with respect to a picture. A model developed to account for the sequence and duration of operations in this task also accounted for the processing of negatives in various situations, such as negatives in instructions and in test items. Another project explored how the information structure of a sentence affects comprehension. Each sentence in a paragraph generally contains some information previously given, and some new information. This project demonstrated that readers treat the two kinds of information differently. This research led to an analysis of what makes good writing: it uses the linguistic devices that minimize comprehension difficulties. A final project explored the use of eye fixations to track the processes that occur during comprehension, examining how subjects fixate a sentence and picture during various comprehension tasks. It was shown that the sequence and duration of the eye fixations can be explained in terms of the mental processes that occur during comprehension. Other papers resulting from the original research are not included here. (Author/CLK)