This article addresses 3 broad challenges of assessment in reading comprehension: (a) explicitly articulating the knowledge and skills students need to recognize and be able to use in comprehending complex texts; (b) understanding how knowledge and skills progress and successively deepen and develop over repeated opportunities to engage in tasks that require critical thinking and interpretation; and (c) how to approach text selection and sequencing. The article examines these challenges in terms of discipline specific comprehension, specifically in the domain of response to literature. It further illustrates how these discipline specific assessment challenges are taken up in Project READI in the design of authentic assessments of literary reasoning.