Some essential books for UPSC civil services preparation include the NCERT textbooks for foundational understanding, 'Indian Polity' by M. Laxmikanth for polity insights, and 'Indian Economy' by Ramesh Singh for economic aspects. For history, 'Indian History' by Bipin Chandra is highly regarded. Candidates should also focus on 'Environment and Ecology' by Kamala Nehru for environmental studies, and current affairs compilations from reputable sources like Yojana and Kurukshetra. Integrating multiple resources ensures a well-rounded understanding and thorough preparation for the exam.