Widely praised as a splendid addition to the literature on the great wave of post-1970 immigration from Mexico-as a result of which an estimated 6 million undocumented Mexican migrants now live in the United States-The World of Mexican Migrants, by acclaimed author Judith Adler Hellman, takes us into the lives of those who, no longer able to eke out even a modest living in their homeland, have traveled north to find jobs. Hellman...