This article proposes an integrated cognitive theory of reading and listening that draws on a maximalist account of comprehension and emphasizes the role of bottom-up and top-down processing. The theoretical framework draws on the findings of previous research and integrates them into a coherent and plausible narrative to explain and predict the comprehension of written and auditory inputs. The theory is accompanied by a model that schematically represents the fundamental components of the theory and the comprehension mechanisms described. The theory further highlights the role of perception and word recognition (underresearched in reading research), situation models (missing in listening research), mental imagery (missing in both streams), and inferencing. The robustness of the theory is discussed in light of the principles of scientific theories adopted from Popper (1959).