The Solemnity of All Saints is a day set aside to celebrate the entire Church Triumphant: those Christians who have gone before us and are in union with the Triune God in heaven.
This, of course, includes all saints we know by name, and even those who haven't been formally canonized by the Church, but nonetheless are truly saints in heaven.
It is only fitting, then, that Catholics are invited to participate in the holy sacrifice of the Mass on All Saints Day to celebrate. The Church requires all Catholics attend Mass on November 1 or the evening before, as a holy day of obligation.
Nativity of Our Lord will be offering the following four Masses in honor of All Saints: