Essential books for UPSC Civil Services preparation include classic texts and comprehensive guides that cover the syllabus effectively. Notable mentions are Indian Polity by M. Laxmikanth, which provides in-depth understanding of the Constitution, Modern History by Bipin Chandra, and General Studies manuals by various authors. Additionally, NCERT textbooks are crucial for foundational concepts, while current affairs compilations enhance knowledge of contemporary issues. These resources collectively build a strong theoretical base and current awareness required for success in the examination.