Tefillin (phylacteries) are ancient ritual items, placed on the head and arm in daily weekday worship. They have been largely eschewed by Reform Jews, but in this chapter a case is made for their inclusion in the ritual vocabulary of contemporary Jews. Through this example, including a debate between Leopold Zunz and Abraham Geiger in the nineteenth century, the question of Jewish ritual observance is considered. The question at stake here is: how should a serious Jew without an a priori commitment to the details of Halakhah relate to ritual observance?