American Missal pages
These pages are from the American Missal, one of the unofficial Anglican missals once used by Anglo-Catholics (Catholic Anglicans) in parts of the Episcopal Church and still used by some Continuing priests.
It splices the American 1928 Book of Common Prayer Communion service into the framework of the traditional Roman Catholic Mass, translated into Tudor English ("thou" etc.) to match the traditional BCP.
The Mass is the offering of Christ's one sacrifice to God the Father for the living and the dead.