This book contains a variety of insights into various religions' views of Abraham. For example:
*Rather than seeing God's covenant with Abraham and that of Sinai as identical, Levenson focuses on the differences between the two covenants. The Abrahamic covenant is unconditional but limited: as a matter of grace, the Jews get nationhood in some form. The Mosaic covenant is broader but very conditional indeed: the Jews actually get self-rule in Canaan, but only as long as the follow God's commandments. While Christians have occasionally argued about the role of Divine grace and human works, Judaism treats both as necessary.
*Levenson has an interesting insight into the Abraham/Isaac relationship. While some commentators point out that they never spoke after the Akedah (the almost-sacrifice of Isaac) Levenson points out that they never spoke before the Akedah either. And while Jews traditionally saw the entire story as about surrender to God's will, Christians saw Isaac as Jesus.
*Both Jews and Muslim legends emphasize Abraham's role as an idol-smasher (although the Biblical text, read literally, does not discuss Abraham's relations with idol-worshippers). By contrast, Christianity downplays this issue, not surprisingly given the Christian tradition of icons.
*Levenson discusses the idea (mentioned in the Mishnah, but expanding into the work of medieval Jewish commenators) that Abraham observed the whole Torah. Although one sage in the Talmud takes a maximalist position, another age, Shimi bar Chiyya, suggests that this view only applies to the seven Noahide laws (basically, a minimal set of ethical rules). This argument continues into the Middle Ages: while Rashi uses this idea to mold Abraham into a model rabbinic Jew, his grandson Rashbam asserts that this concept applies only to the moral commandments that are generally recognized by most of humanity.