Boy choirs are one of the oldest musical traditions in the Western world. While audiences admire boy singers for their distinctive treble notes, boys who sing in soprano voices have to contend with the notion that they're doing something effeminate, even emasculating, because they sing in a vocal range typically reserved for women and girls. Known as the "unchanged trebles" within choirs, boys who sing in soprano voices defy prevailing norms of traditional masculinity. What do boy choirs represent in a culture that increasingly sees gender as an individual choice rather than a fixed, biological category? And is this tradition, which is rooted in exclusion of girls and women, one worth saving? In Unchanged Trebles, Rebekah Peeples charts an unexpected, thought-provoking, and deeply personal journey into the peculiar world of contemporary boy choirs, where boys learn to do something together that they're often embarrassed to do alone: sing in their soprano voices. Considering her experience as the unlikely mother of a boy soprano alongside dozens of interviews with current directors and former choristers, she argues that some of the tools for creating a more gender-inclusive future can be found in an ancient tradition that has long recognized gender fluidity within the pre-pubescent male body. With humor, insight, and the voice of a gifted storyteller, Unchanged Trebles explores a cultural tradition in which singing and expressing emotion are encouraged for boys, showing them a more expansive form of masculinity as they transition from boyhood to manhood.