This paper presents a historical overview of the gradual shift in the moral and philosophical foundations of American society as reflected in the content of textbooks. Working from the premise that textbooks mirror changing social values, the paper cites various studies that trace the trend, over the past 200 years, away from an emphasis on religious principles and appropriate social behavior toward an emphasis on understanding and amusement. After presenting examples of arguments by prominent American and British thinkers both for and against this trend toward secular humanism, the paper describes the current diversity of public opinion on the controversial issue of textbook content. Quoting extensively from a study conducted by Paul C. Vitz, the paper reports that most of today's textbooks neglect the history of religion and the portrayal of traditional family values, sex roles, the work ethic, and patriotism. The paper cites another source in support of this study and concludes with (1) a brief review of predictions by some social scientists and (2) an appeal to educators to reassess the values and foundations underlying current reform movements. (IW)