Although he was arguably Elizabeth i's favourite musician at court from the mid-1570s, William Byrd (c. 1540–1623) also came to be known as one of the monarch's most resolutely Roman Catholic subjects. Generally acknowledged as England's finest composer during the second half of the sixteenth century, his extraordinary musical output spans nearly seven decades. Byrd's career successes began in 1572 with his initiation into the Gentlemen of the Chapel Royal, the elite body of musicians within which he had probably served as a boy chorister from the late 1540s. By 1580 his music had already been insinuating the occasional reference to the plight of persecuted English Catholics, typically through biblical texts centred on themes of captivity and oppression. Similarly during the 1580s and '90s, Byrd established (and later maintained) close ties with Jesuit missionaries positioned in England. In contrast with many like-minded compatriots, he was never openly persecuted by government authorities; his safety was secured by patrons among the Catholic nobility and by the queen herself. Byrd's exposure to the Ignatian devotional programme, his role in clandestine recusant liturgies and his intimate proximity to the executions of condemned coreligionists (and influential friends), shaped and defined his creative impulses during the final decades of his life. It is in this light that Kerry McCarthy's important book presents the summa of Byrd's sacred oeuvre and the musical embodiment of his faith, Gradualia (1605/1607). Printed successively in two volumes, Gradualia offered an unprecedented cycle of polyphonic mass propers (introit, gradual, alleluia or tract, offertory and communion) for the chief festivals of the Roman church year. For ecclesiastical historians, theologians, liturgiologists and literary critics mystified by musicological analysis, McCarthy provides an interdisciplinary tour de force. She unpicks Byrd's prowess as musical architect and ritual exegete, revealing the Gradualia cycle as a representation of the devotional ideals and priorities of English recusant culture. McCarthy achieves her objective by drawing from three principal bodies of literary evidence: Byrd's written prefaces to published volumes of his music over a period of three decades (chapter i); the spiritual exercises of St Ignatius Loyola – the benchmark of devotional discipline in Counter-Reformation Europe (chapter ii); and the contemporary liturgical wisdom evinced in printed ritual exegeses, deriving from seminal texts of the high Middle Ages, reinterpreted in accordance with Tridentine reforms and partisan religious conflict (chapter iii). Analytically, McCarthy links the formal design of Byrd's polyphonic propers with their corresponding ritual ‘text types’ at various levels of magnification. Examples include explanations of the introit as rhetorical ‘exordium’, the offertory as ‘epigram’ and the communion as culminating ‘peroration’ (chapter iv). Having scrutinised these types as genres in their own right, McCarthy equally highlights their collective coherence within the greater festal narrative at hand. On the grounds of musical modality, clef configuration and vocal scoring, she uniquely identifies Byrd's division of the entire Gradualia cycle into three distinct macro-narratives (chapter v). McCarthy's book stands at the vanguard of musicological synthesis for this period, promising to offer useful insights for analysts in adjoining disciplines.