How was it that Jew­ish com­mu­ni­ties liv­ing under Chris­t­ian rule in the Mid­dle Ages were able not sim­ply to sur­vive, but to flour­ish in num­bers and intel­lec­tu­al cre­ativ­i­ty? This is the cen­tral con­cern of Robert Chazan’s new book, a fast-mov­ing sur­vey that draws upon mate­r­i­al pub­lished in sev­er­al of his ear­li­er books. Start­ing from the bib­li­cal pas­sages that ani­mat­ed dis­cus­sions through­out the medieval peri­od, Chaz­an explains how each com­mu­ni­ty inter­pret­ed these pas­sages dif­fer­ent­ly, and the sig­nif­i­cance that these con­flict­ing inter­pre­ta­tions had for how Jews and Chris­tians thought of them­selves and each oth­er. This par­al­lel approach rein­forces what is per­haps Chazan’s main point — that Jew­ish com­mu­ni­ties were respond­ing to Chris­t­ian ones, defend­ing them­selves against the chal­lenge posed by the oth­er. In his epi­logue, Chaz­an points to the char­ac­ter­is­tics of medieval Euro­pean Jew­ry that he believes helped those same Jew­ish com­mu­ni­ties play a high­ly suc­cess­ful role in the mod­ern world.