Reading skills are the key building blocks of a child's formal education. Yet, the national statistics on literacy attainment are profoundly distressing: two out of three American fourth graders are reading below grade level and almost one third of children nationwide lack even basic reading skills. This study reports on an evaluation of the Reading Partners program, which uses community volunteers to provide one-on-one tutoring to struggling readers in under-resourced elementary schools. In the years since its inception, Reading Partners has grown to serve more than 7,000 students in over 150 schools throughout California, Colorado, Maryland, New York, Oklahoma, South Carolina, Texas, Washington, and Washington, DC. To answer questions about the effectiveness of the Reading Partners program and the potential for volunteer tutoring more generally to help improve the reading proficiency of struggling readers, the evaluation included an implementation study, an impact study (in which students were randomly assigned within schools to receive Reading Partners or to a control condition) and a cost study. Together, these three facets of the evaluation are designed to address the following broad research questions: (1) In what context was the Reading Partners program implemented and was it implemented as intended or with fidelity? How much variability in fidelity of implementation was observed across the sites? What factors contributed to any observed variability?; (2) On average, did the Reading Partners program have a positive impact on students' reading proficiency across three key components of early reading ability: sight word reading efficiency, reading fluency and comprehension?; and (3) What resources are needed to implement the Reading Partners program as described in the evaluation and what proportion of the costs of implementing the program are borne by the school? The sample for the study consists of 19 Reading Partners schools that were recruited to participate in the evaluation. The 19 participating schools were spread across 12 school districts. There were 16 schools in California, two in New York, and one in Washington D.C. All of the schools were established Reading Partners sites; eight of the 19 schools were in their second year of operating, while the rest had been operating a Reading Partners center for 3 or more years. A total of 1265 2-5th grade students in the 19 schools participated in the evaluation. The final respondent sample (those that took at least one follow-up assessment) included 1166 students. This represents a response rate of 91.9 percent for the program group and 92.4 percent for the control group. The findings all suggest that the Reading Partners model "works"--i.e., it produces measurable impacts in reading skills among participants and that the program was effective in helping students with a fairly broad range of reading abilities and from a variety of different grade levels and backgrounds. The cost data will shed light on how much the program costs relative to the reading impacts it generates. Tables are appended.