This book includes the description and development of a scale for evaluating the mental development of young children. Starting from concepts as controversial as mental age, IQ and intelligence measurement along with factors as important as education and context, these authors have recovered the application of development tests to the early years of childhood. Based on the works of Gessell and Bühler, they do not treat the tests specific to each age as the levels of a scale that would measure psychic development, but as an analysis instrument that is as adapted as possible to the specific age of each child. They try to improve the scale by making it more rigorous and manageable.