At the Walters in Baltimore, through the end of January:

For the first time, the Walters will display its superb collection of illuminated missals, liturgical manuscripts and printed books for the celebration of the Catholic Mass.  This exhibition of manuscripts, printed books, and altar furnishings will investigate the changing imagery of the missal in the Middle Ages, with particular emphasis on illustrations for the Canon of the Mass.  The exhibition coincides with the celebrations marking the reopening of Baltimore’s historic Basilica of the National Shrine of the Assumption of the Virgin Mary.