He is the author of the immensely popular book on liberal theology, "When Bad Things Happen to Good People", which was widely read not just in Jewish circles, but became a best seller due to its adoption by many liberal Protestant Christians as well. This book deals with questions about God, Omnipotence and Theodicy.
Kushner has written a number of other popular theological books, such as "How Good Do We Have to Be?", "To Life!" and many others. His most recent contribution is his being one of the editors of "Etz Hayim: A Torah Commentary", the new official Torah commentary of the Conservative Jewish movement, which was jointly published in 2001 by the Rabbinical Assembly and the Jewish Publication Society.