The manuscript edited in these volumes is a fine and elaborate missal of Westminster Abbey, given by Nicholas Lytlington (abbot 1362-1386) and often referred to by his name. As well as its importance as a particularly full missal text from a royal abbey (it includes an extensive coronation ritual), it is also the only monastic representative of a `Sarum' type of sacramentary to have received a modern edition. John Wickham Legg's publication of this manuscript was an early milestone in the Henry Bradshaw Society programme, and is particularly notable for its extensive critical notes: employing over fifty other manuscripts, as well as printed sources, Legg provided a commentary which gives an extraordinarily comprehensive view of texts for the celebration of mass in the middle ages. His work remains, over a century after its publication, a fundamental and indispensible tool for the study of medieval mass-books, both insular and continental. Reissue; First published 1891.