No man is an island, not even Jesus, as John Meier writes in Companions and Competitors, the third installment of his four-part series, A Marginal Jew: Rethinking the Historical Jesus. The first volume, an overview of Jesus' background, chronology, and early years, was followed by a second that analyzed Jesus' most important messages and deeds. Here, Meier explains his conviction that `No human being is adequately understood if he or she is considered in isolation from other human beings.` He leads readers through the concentric circles of companions (including the followers who became his disciples and apostles) and competitors (such as Pharisees, Sadducees, Essenes, Samaritans) that shaped Jesus' life in first-century Palestine. Meier, a priest and New Testament scholar at Notre Dame, writes in the engaging, methodical style of an astringently avuncular professor: chapters are carefully outlined, with straightforward headings such as `Points of Comparison and Contrast,` `Caveats on Comparisons,` and `The Sheer Oddness of Jesus`). His findings, particularly his explanation of `the essentially Jewish nature` of Jesus' relationships, are a valuable addition to the field of Historical Jesus scholarship.