Reading, like all areas of human learning, is complex and multidimensional. Educational psychology has an opportunity to contribute further to a science of reading, and potentially to a science of reading instruction, by expanding its traditional theoretical and methodological orientations to embrace this complexity. Topics central to this effort are discussed in the five papers in this special issue. They make apparent the need to reconceptualize reading comprehension as involving a multitude of cognitive and metacognitive processes shaped by the purposes and sociocultural contexts of its enactment and reflecting developmental, linguistic, and ethnic variation among learners. Addressing this complexity is critical to equitable reading comprehension instruction and assessment that meets the needs of an increasingly diverse population.