“Who is allowed to become a Jew” is a ques­tion that qui­et­ly attach­es itself to the much-dis­cussed issue of who is a Jew – although, per­haps not so qui­et­ly these days. The ongo­ing argu­ment in Israel over con­ver­sion has roiled that coun­try and rat­tled this one. Co-authors David Ellen­son and Daniel Gordis illu­mi­nate the chal­lenges of that spe­cif­ic debate, and those con­fronting Jew­ish com­mu­ni­ties else­where, by tak­ing a look at his­to­ry. They avoid offer­ing their own per­son­al reme­dies: instead they present an aggre­ga­tion of respon­sa from Ortho­dox rab­bis in Europe, the Unit­ed States, and Israel from the nine­teenth through the twen­ty-first cen­turies, let­ting the past inform the present.

Do not make the mis­take of assum­ing that a col­lec­tion of Ortho­dox legal opin­ions from years ago is dry read­ing. Ellen­son and Gordis are sto­ry­tellers – fru­gal but skill­ful at lay­ing out the con­text and con­tent of the dili­gent­ly halakhic, yet ulti­mate­ly con­flict­ing, deci­sions made by var­i­ous rab­bis in dif­fer­ent loca­tions over more than two cen­turies. Though all of the rab­bis con­sult­ed the same halakhic texts and com­men­taries, their var­ied con­clu­sions make it clear they were influ­enced, how­ev­er reluc­tant­ly, by the ​“facts on the ground” of their par­tic­u­lar place and time. Specif­i­cal­ly high­light­ed is how the pres­ence of increas­ing­ly siz­able non-Ortho­dox denom­i­na­tions exert­ed pres­sure on many of these rab­bis and their rul­ings.

The book begins as moder­ni­ty presents the Jew­ish pop­u­la­tion of Europe with the com­pli­ca­tions of inclu­sion in non-Jew­ish soci­ety – increased inter­mar­riage, more Gen­tiles want­i­ng to con­vert to Judaism, ques­tions of Jew­ish iden­ti­ty – and con­cludes with the con­tentious cir­cum­stances aris­ing from mas­sive Russ­ian immi­gra­tion to the State of Israel. The result is a com­pelling, pen­du­lum-swing­ing nar­ra­tive and a sober­ing view of the kalei­do­scop­ic dif­fi­cul­ties that con­ver­sion can present.