Here's the story: a reverend and a rabbi start a blog. In 2008, Baptist minister Michael Smith and Jewish rabbi Rami M. Shapiro began a virtual conversation via blogspot.com. Called "Mount and Mountain," the blog recorded a long-running dialogue between Mike and Rami in which the pair interpreted, argued about, and interrogated two key texts drawn from the canons of their respective religions: the Ten Commandments from the Torah, and the Sermon on the Mount from the Gospel of St. Matthew. This book, focused on the Sermon on the Mount, represents the second half of Mike and Rami's dialogue. In...