Today American elementary and secondary education is under active attack for alleged failures or shortcomings of various kinds. In the minds of those responsible for running the schools, much, if not most, of the criticism is distinctly ill-founded and irresponsible. School personnel have long been decrying outmoded practices and promoting new ones, many of the latter bearing the brunt of current condemnations. But present lay criticism seems to have caught a large segment of school personnel quite unprepared to meet it; hence responses are often unconvincing, recriminatory, or yielding. If the educational profession is to maintain past and present gains and to achieve new ones, it must know what has been done in the past, what has proven unsatisfactory and what satisfactory, what innovations have been tried and what has come of them, and why we have come to do what we are now doing. This perspective requires a study of the growth of American educational thought and practice, for if we do not know history, how can we avoid repeating the errors of our predecessors?