Recommended books for UPSC Civil Services preparation include foundational texts and comprehensive study materials. For general studies, NCERT books provide a solid base, while reference books such as India Year Book, Laxmikant's Indian Polity, and GC Leong's Physical Geography are highly regarded. For specific subjects, aspirants often refer to standard texts pertaining to their optional subjects. Additionally, using online resources, current affairs magazines, and compilations can supplement learning. A curated list tailored to one’s strengths can enhance effective study.