Jewish Religion (www.ajrsem.org) and the co-founder of the Kohenet Institute, a program in Jewish women's spiritual leadership (www.kohenet.org). Rabbi Hammer is a midrashist, a ritualist, and the author of two books: Sisters at Sinai: New Tales of Biblical Women (Jewish Publication Society, 2001) and The Jewish Book of Days: A Companion for All Seasons (Jewish Publication Society, 2006). She has been exploring the stories of biblical women since her college days and continues to discover new layers of their legends and lives. Her literary writing has been published in journals and newspapers such as Zeek Magazine, Lilith Magazine, The Journal of Feminist Studies in Religion, Natural Bridge, The Torah: A Women's Commentary, and The Forward.

She has been published on-line at ritualwell.org, myjewishlearning.org, and other websites. Her academic work has appeared in The Journal of Religion and Literature, Nashim: A Journal of Jewish Women's Studies and Gender Issues and G'vanim: The Journal of the Academy for Jewish Religion. Rabbi Hammer was ordained at the Jewish Theological Seminary in 2001 and holds a doctorate in social psychology from the University of Connecticut. She received a BA at Brandeis University. She lives in Manhattan with her partner Shoshana Jedwab and her daughter Raya Leela. Jill Hammer and Shir Yaakov Feit have been collaborating since 2004, when they co-created Tel Shemesh, a website celebrating earth-based Judaism.

In 2006, when Hammer co-founded the Kohenet Institute with Holly Taya Shere, Feit became Kohenet's art designer and webmaster, and designed the Kohenet prayerbook. They also collaborate in prayer and ritual contexts at the Isabella Freedman Jewish Retreat Center and at Romemu in New York City. They are pleased to be collaborating on this Omer calendar.