This Edition of UPSC Prelims Paper 1 (General Studies) book has been made to meet the requirements of candidates appearing in UPSC Prelims 2021. This volume covers the questions of the UPSC Paper 1 of the last 27 years (1994-2020) including of latest conduct exam of UPSC Prelims 2020. For easy understanding and to provide in-depth explanations, all questions have been classified in six major chapters and each chapter is again divided into topics, so that aspirants can adopt the systemic approach of study. All chapters are prepared according to the syllabus of the UPSC Prelims Paper 1, which History of India and Indian National Movement, Geography of India and World, Polity and Governance, Indian Economy and Social Development, General Science, Technology and Environment, General Knowledge and Current Affairs. The book is also contain a topic-wise analysis of previous years UPSC Prelims questions which is necessary for proper strengthening of subjects.