A landmark series of studies devoted to the revision of the Book of the Common Prayer -- Volume Four revisits the Church Calendar and the Eucharist.The creation of the landmark 1979 Book of Common Prayer was the fruit of nearly four decades of discussion within the Episcopal Church. Prayer Book Studies is a series of official reports by the Church's Standing Liturgical Commission that were published irregularly over the course of that period, representing the work of the committees deliberating over and drafting the materials that would eventually become the 1979 revision. These reports provide an extraordinary window into the work of leading liturgical scholars during an age characterized by huge transformation in the fields of liturgy. Long out of print and unavailable, these reports, collected in nine volumes, are an invaluable resource for liturgical scholars and clergy.The two studies in Volume 4 revisit two important subjects addressed in earlier work: the Calendar and the Eucharist. Notably, their publications in 1963 and 1966 address and incorporate important ecumenical developments resulting from the dramatic events of Vatican II (1962-1965).