This book has presented an account of cognitive development from birth through maturity to old age. Each chapter discussed a major stage in the individual’s development. The fact that four-fifths of this book has been devoted to the years from birth to 12, leaving only one-fifth for the rest of the life span, is an indication of the disproportionate amount of research into cognitive development in childhood and youth, resulting in the virtual neglect of maturity and old age. It is true that development is more rapid and more apparent during the early years but this does not mean that development stops with early adolescence.