Participation in shared-reading experiences is associated with children's language and literacy outcomes, yet few standardized assessments of shared-reading quality exist. The purpose of this study was to describe the psychometric characteristics of the Systematic Assessment of Book Reading (SABR), an observational tool designed to characterize the quality of classroom-based shared-reading sessions in early childhood settings. Participants included 105 preschool teachers. The quality of teachers' videotaped, whole-class shared-reading sessions was examined using the SABR. Reliability levels for each of the SABRs five constructs were examined, as well as delayed alternate-form reliability and inter-rater reliability. The tools' factor structure and construct validity were also assessed. Findings provide initial validation and preliminary evidence that the SABR is a reliable and valid tool. Potential uses for early childhood researchers, teachers, and allied professionals are described. (Contains 7 tables.)