This introductory paper to the special issue “Reading in Science and Mathematics” presents four major theoretical perspectives of reading, literacy, and language that underpin many studies in this area, including the nine articles selected for this issue. It first outlines several new developments and contemporary issues that drive the growing importance of reading in science and mathematics. It then presents the perspectives that inform and situate the authors’ research as reported in this special issue, followed by a brief introduction of their articles situated within each of the perspectives. The four perspectives are reading comprehension, scientific/mathematical literacy, disciplinary literacy, and linguistic/semiotic meaning-making. The purpose in discussing these perspectives is to map out the theoretical terrain in the field and connect the key ideas within the research on reading in science and mathematics.