Book of Common Prayer (Unitarian)

Since the 18th century, there have been several editions of the Book of Common Prayer produced and revised for use by Unitarians. Several versions descend from an unpublished manuscript of alterations to the Church of England's 1662 Book of Common Prayer originally produced by English philosopher and clergyman Samuel Clarke in 1724, with descendant liturgical books remaining in use today.

Clarke, a Semi-Arian and Subordinationist, viewed the doctrine of the Trinity as theologically unsound and saw the 1662 prayer book's inclusion of elements like the Athanasian Creed as perpetuating these errors. Clarke's manuscript alterations emphasized the excision of Trinitarian references in favor of prayers directed toward God the Father. Theophilus Lindsey would build upon Clarke's work after receiving a copy of the changes, publishing his own series of Unitarian prayer books from 1774 onward. Lindsey's Essex Street Chapel in London, the first Unitarian church in England, utilized these prayer books for worship. When an Essex Street Chapel congregant introduced James Freeman of King's Chapel in Boston to Lindsey's prayer book, Freeman further edited its liturgies and convinced his congregation to adopt his revision in 1785.

These Unitarian forms were among a trend of Nonconformist efforts to revise the 1662 prayer book through the 18th and 19th centuries; the Anglican prayer book remained the primary basis for English Unitarian worship literature until 1861. The Unitarian revisions influenced other prayer book revision efforts, including John Wesley's The Sunday Service of the Methodists and the American Episcopal Church's first attempted prayer book revision. The King's Chapel prayer book, currently in its ninth edition as first published in 1986, remains that congregation's standard liturgical text.