For many years, school exams in India have rewarded students who can repeat what is written in the textbook. The National Education Policy (NEP) 2020 and the National Curriculum Framework for School Education (NCF-SE) 2023 ask for something else: assessment of conceptual understanding, application and problem-solving rather than memorisation. Open-book examination (OBE), in which students may consult textbooks, notes or other approved resources while answering, is one format proposed to serve this aim. The Central Board of Secondary Education (CBSE) experimented with a version of it called the Open Text-Based Assessment between 2014-2017 and has now approved open-book assessment for Class 9 from the 2026-27 session. This conceptual paper looks at what OBE means, the forms it takes, why school education needs it and grounds the format in the revised Bloom's taxonomy and constructivist learning theory. It compares open-book and closed-book examinations, maps OBE onto the assessment provisions of NEP 2020 and NCF-SE 2023 and considers the skills it can develop as well as its advantages and limitations. A review of the Indian experience leads to a phased strategy for schools. The central argument is that OBE can help the schools shift away from rote learning only if question design, teacher preparation, student orientation and equal access to materials are explored together.