This paper reports the findings of a small-scale qualitative study that explored the perceptions of and approaches used by UK school librarians and teachers in the design and use of reading lists. The research question was: "What is the best way to construct reading lists to maximize their benefit in the school library or classroom?" The research strategy adopted for the study was thematic analysis. The data collected from five semi-structured interviews was analyzed and a thematic map produced. The analysis identified four key themes that shape construction of reading lists: content, user, purpose, and format. The content was selected using a range of methods, including patron-driven, literary merit, exclusion, textual variety, and curriculum. The user was central to the design with reading lists being parent-driven and pupil-centered. The purpose was situated within a wider reader-development curriculum. However, the participants perceived that the reading list was a less-effective method of reader development than face-to-face interaction with pupils. Four recommendations to improve practice in similar contexts are suggested. The conclusion reached was that UK preparatory school librarians' and teachers' construction of reading lists is a complex practice that attempts to balance pupils' reading for pleasure with their needs for literacy attainment.