The collective monograph "Development of a Screening Instrument Set for Psychological Assessment to Identify Early Developmental Risks in Children. Volume I: Theoretical Justification of Screening Constructs and Accessibility of Development-Promoting Interventions" presents a comprehensive framework for early childhood psychological screening in Latvia. It is intended for professionals working with early childhood development, including general practitioners, pediatricians, psychologists, audiologists, speech therapists, special education teachers, preschool educators, students, and policymakers in inclusive education. This volume addresses three critical aspects of strengthening child mental health monitoring and improving inclusive education at the preschool level: Development of a novel screening tool – The monograph introduces a scientifically validated, Latvia-specific, electronically administered Early Childhood Development Screening Instrument Set (BAASIK), designed to identify early developmental risks in accordance with the ICD-11 classification system. Analysis of intervention accessibility – It examines the availability and effectiveness of early intervention strategies for children (ages 1–6) with developmental risks, comparing global and Latvian approaches. Standardization of assessment tools – The monograph compiles psychological assessment instruments that require adaptation and standardization for the Latvian child population, ensuring high-quality and reliable psychological evaluations. A particular focus is placed on the early identification of learning difficulties in reading, writing, and mathematics, as well as on addressing the challenges related to accessing adequate support services in preschool settings. The findings and recommendations in this monograph serve as a foundation for advancing early childhood psychological assessment and fostering inclusive education policies in Latvia.