A breviary is a liturgical book central to Christian prayer, containing texts for the canonical hours—seven fixed prayer times rooted in early Christian tradition. Historically, it evolved from varied regional practices, such as the Roman Breviary standardizing Catholic liturgy, while Lutheran and Oriental Orthodox traditions preserved unique versions like the Brotherhood Prayer Book or the Shehimo.
Though authors like Seneca noted its role as a "summary" of prayer, the breviary’s essence lies in its structured combination of psalms, hymns, and prayers, reflecting both communal and personal devotion across centuries. Its lasting forms, from medieval manuscripts to modern liturgical reforms, highlight its flexibility as a spiritual guide.