A central aspect of federal educational policy making over the past half century has been attempts to fund interventions that close the achievement gaps that exist on measures of reading proficiency. The reading achievement gap between children from more and less economically advantaged families is substantial and has been persistent. Though there is evidence that this achievement gap has narrowed over time (Grissmer, Kirby, Berends, & Williamson, 1994), a recent National Assessment of Educational Progress in reading provides strong evidence of the pervasive nature of this seemingly intractable problem (Perie, Grigg, & Donahue, 2005). Though 77% of more economically advantaged fourth-grade stu- dents achieved above the basic level proficiency, only 46% of poor students (eligible for free or reduced-priced meals) achieved this modest level of reading development. But the failure of the various recent federal educational initiatives to close this reading achievement gap may stem from a failure of policy makers to focus attention on what seems a primary source of the existing achievement gap: summer reading setback.