While from a conceptual point of view, screening and scoping are separate notions in the environmental impact assessment procedure, they are still closely linked. This doctoral thesis addresses scoping (preliminary proceedings) and screening (case-by-case review) separately, dedicating an entire chapter to potential overlaps. The chapter on scoping focuses on the process of defining the scope, a process that presents a challenge for any project applicant. The thesis also takes account of the fact that, given the variety and diversity of projects submitted for environmental impact assessment, it may be necessary to deviate from this standard formula.The chapter on screening concentrates on the field of application of case-by-case review, providing an extensive description of the topic and illustrating different legal opinions in instances where there is no case law.In addition, the thesis also addresses for both screening and scoping the role of the general public, as this is becoming more and more important. In doing so, the thesis analyses the current legal situation in Austria and its conformity with European Union law.