Autism Spectrum Disorder (ASD) is recognized by persistent deficits in verbal/social communication and social interaction in multiple contexts, including deficits in social reciprocity, in non-verbal communication behaviors used for social interaction and in abilities to develop, maintain and understand relationships. The aim of this research was to screen for early signs of childhood autism in Primary Health Care. In this way, this book provides information on early screening for signs of autism in children treated in Primary Health Care and we hope that it can bring effective understanding to you, the readers. Furthermore, we hope that you will be able to appropriate this knowledge and give it concrete meaning in terms of contributing to the development of socialization and autonomy for people living on the Autism Spectrum, with a view to improving their quality of life.