Fred Cook, by his own admission, is a man in search of an identity. From his teenage years through his early 30s, he filled that void with neo-Nazism. But over the past decade, he has grown to fill it with Judaism. Cook, 43 and a Philadelphia resident, has spent the past year-and-a-half converting to Judaism through Congregation Rodeph Shalom on North Broad Street. In July, his beit din will rule on his conversion. If the three religious authorities accept Cook into the faith, the convert will enter the mikveh. He already wears a Star of David necklace with the star...