In this chapter an attempt is made, in the light of evidence from the United States and Canada, to explain in general terms the ebb and flow of private school options. Both public and private school growth and decline are affected by demography. Thus, a massive drop in Catholic school enrollment from 1966 to 1981 reflects, in part, a birthrate decline and a migration of Catholics from central cities, where many Catholic schools existed, to suburbs, where there were few Catholic schools. But unlike public school attendance, which rarely involves user fees and is considered normal if not laudatory in the United States and parts of Canada, private school attendance generally occurs when parents decide to depart from normal practice, incurring extra cost, extra effort (many private school patrons must drive their children considerable distances to school), disruption of their children’s friendships (many private school students are not in the schools which most of their neighborhood friends attend), and sometimes social disapproval. To a far greater extent than public school enrollment, then, private school enrollment depends on patron motivations. To return to the Catholic example: Even if the Catholic birthrate were high and Catholic schools were universally accessible, those schools would soon collapse unless many Catholic parents considered them worth extra expense and effort. Also, while public schools are everywhere available, parents often cannot find the private schools they prefer. Some schools exist primarily for certain religious and ethnic groups. Schools of some types are available only in a few major cities. Some schools are beyond the fiscal reach of most people. It is no accident, in this regard, that religious options are more plentiful in private schools than curricular or pedagogical options. Most religiously oriented schools enjoy subsidies from religious groups. Many schools open in the facilities of churches and synagogues, thus avoiding major expense. Sometimes churches and other denominational agencies directly sponsor schools. Even when they do not, they often assist by taking special collections, or their members provide free labor. Many Jewish day schools are subsidized through Jewish community funds.