Relatively scarce in the early years of the United States, moral tales were increasingly popular in the nineteenth century (see Introduction). Frequently based on a line of scripture of a moral precept, these works functioned to convey the ideals of virtuous conduct (obedience, forgiveness, and responsibility) through narrative means. In this sense, they are companions to conduct literature. Stories appealed to children through imaginative and emotional identification in a way, frequently representing scenes of piety and conversion. Most denominations tailored these stories to suit their own doctrinal needs.
This era witnessed a growing complication between writing and piety. The lists of titles in this collection or in the library catalogues sold by Sunday School Unions reveal that fictional tales comprise about one third of them but it was clearly the fastest growing and most frequently reprinted section of most publishers lists, especially after mid-century. Not surprisingly, fiction even when adhering to scriptural models was a controversial subject in Sunday school education. Controversy prevailed in regard to whether fiction was healthy for young children. Many religious authorities insisted that fiction should be excluded entirely, in that it tended to be sensational, prurient, or fantastic, corrupting the imaginations of the young or giving them a false sense of reality. The purveyors of evangelical children's literature were conflicted over what constituted appropriate material and that in gaining a wider audience they might lose control of their doctrine and message.
It was clear to most observers that children returned time and again to the fictional works and would seldom take out the books "of more solid religious character." Because teachers saw that it was most important to cultivate a taste for reading in their young students, they began to rely more and more on "entertaining tales with moral messages." The concern with fiction lay in the sense that not only could it lead to fantasy or sensationalism but also to kind of license with scripture itself, unorthodox or personal interpretations, and secular opinion. This was another reason that the Sunday school unions formed publication committees to oversee and regulate content.
— Stephen Rachman, Department of English, Michigan State University