Jill Hammer co-founded the Kohenet Hebrew Priestess Institute to offer women alternative ways of connecting with Jewish tradition by focusing on the sacredness of the body and the earth. Hammer graduated from Brandeis University in 1991, earned a PhD in social psychology from the University of Connecticut, and received rabbinic ordination from the Jewish Theological Seminary in 2001. As a woman—and particularly as a lesbian—she explored the concept of God as female or dual-gendered (including drawing on goddess imagery from other religions), and questioned why Jewish tradition shifted away from allowing women to be prophets and judges. Soon after ordination, she became the director of spiritual education at the trans-denominational Academy for Jewish Religion in Riverdale, New York. In 2005 she and Taya Shere co-founded Kohenet, and as of 2016, Hammer continues her work at both institutions. Among her published works are Sisters at Sinai: New Tales of Biblical Women (2001), The Jewish Book of Days: A Companion for All Seasons (2006), Siddur HaKohanot: A Hebrew Priestess Prayerbook (2010), ​​and Undertorah: An Earth-Based Kabbalah of Dreams (2021).