This book constitutes the refereed proceedings of the fourth International Conference on Informatics in Secondary Schools - Evolution and Perspectives, ISSEP 2010, held in Zurich, Switzerland in January 2010. The 14 revised full papers presented together with 6 invited papers were carefully reviewed and selected from 32 submissions. A broad variety of topics related to teaching informatics in secondary schools is addressed ranging from national experience reports to paedagogical and methodological issues. Contributions solicited cover a variety of topics including but not limited to accessibility, assessment, classroom management, communication skills, computer science contests, computers and society, courseware, curriculum issues, research in informatics education, diagnostic teaching, empirical methods, ethical/societal issues, gender and diversity issues, high school/college transition issues, information systems, information technology, interdisciplinary courses and projects, laboratory/active learning, multimedia, object-oriented issues, pedagogy, student retention and persistence, role of programming and algorithmics, using emerging instructional, technologies and web-based techniques/web services.