The history of literacy research is like a series of slow, undulating waves lapping against a shoreline. Just as a wave reaches its crest, it wanes as another overtakes it. The ebb and flow of literacy scholarship follows a similar pattern. In this essay we focus on the topical shifts in literacy research during the last 140 years, using the language arts as our analytic frame (i.e., reading, writing, speaking, listening, viewing, & visually representing) (NCTE/IRA, 1996). Six overlapping periods of literacy research are outlined below. Beginning with the study of physical processes associated with literacy(1870s-1920s), the succession of overlapping topics include the effectiveness of literacy instruction (1910s-1980s), the cognitive modeling of literacy processes and development (1970s-mid-1980s), the development of literacy in social, cultural, and linguistic contexts (early 1980s-early 2000s), the impact of policy on literacy instructional research (late 1950s-early 2000s), and the expansion of literacy across media and spaces (1950s-present). Literacy research in each of these periods focused on varying aspects of the six language arts.