In this lecture, Alan Rosen considers the special manner of witness found in Holocaust-era calendars composed in ghettos, in camps, and in hiding. The marking of fast days and festivals tell a remarkable story; the form, organization, and languages of the calendars convey a related one. And as with testimony in general, what is omitted—a date or a month, a name or a script—speaks volumes. At times, moreover, such calendars served as vehicles for sacred writings, images and symbols as well as for camouflaged defiance. The lecture is based on his recent book The Holocaust’s Jewish Calendars: Keeping Time Sacred, Making Time Holy.