Books for UPSC Civil Service Main Exam overlap with many books recommended for Prelims. But Mains stage demands certain additional books as there are new topics like Foreign Relations, Internal Security, Ethics etc.

UPSC Books for Indian Polity and Constitution

1. Indian Polity – by M. Laxmikanth
2. Important Acts that Transformed India – by Alex Andrews George
3. Important Judgments that Transformed India – by Alex Andrews George

UPSC Books for Indian History and Culture

1. Indian Art and Culture – by Nitin Singhania
2. Ancient and Medieval India – by Poonam Dalal Dahiya
3. Modern Indian History – by Sonali Bansal and Snehil Tripathi

UPSC Books for Indian Geography and World Geography

1. Certificate Physical And Human Geography – by Goh Cheng Leong
2. Geography of India – by Majid Husain
3. Oxford Student Atlas for India

UPSC Books for the Indian Economy

1. Indian Economy – by Ramesh Singh
2. Indian Economy – by Nitin Singhania
3. Indian Economy Key Concepts – by Sankarganesh Karuppiah

UPSC Books for Science and Technology

1. Science and Technology – by Ravi P. Agrahari

UPSC Books for Environment – Ecology, Biodiversity and Climate Change

1. Environment – By Shankar IAS

UPSC Books for Current Affairs

1. India 2021 Yearbook – by Rajiv Mehrishi
2. The Malayala Manorama English Yearbook 2021  –  by Mammen Mathew
3. India 2021 – Publications Division Paperback – by Publications Division

IAS Books for Essay (UPSC Mains Essay Paper)

1. Selected Contemporary Essays Paperback – by Saumitra Mohan
2. 151 Essays – by Disha Experts

IAS Books for India Since Independence (Part of UPSC Mains GS1 Paper)

1. Post-Independence India: For Civil Services Examinations – by Sonali Bansal and Snehil Tripathi

IAS Books for World History (Part of UPSC Mains GS1 Paper)

1. World History – by Krishna Reddy

IAS Books for Indian Society (Part of UPSC Mains GS1 Paper)

1. Indian Society: Themes and Social Issues – by Nadeem Hasnain

IAS Books for Governance (Part of UPSC Mains GS2 Paper)

1. Governance in India Paperback – by M. Laxmikanth

IAS Books for Foreign Relations of India (Part of UPSC Mains GS2 Paper)

1. International Relations – by Pavneet Singh

IAS Books for Internal Security (Part of UPSC Mains GS3 Paper)

1. Challenges to Internal Security of India – by Ashok Kumar and Vipul Anekant

IAS Books for Ethics, Integrity, and Aptitude (UPSC Mains GS4 Paper)

1. Lexicon for Ethics, Integrity & Aptitude for IAS General Studies – by Niraj Kumar
2. Ethics, Integrity, and Aptitude – by M. Karthikeyan
3. Ethics, Integrity & Aptitude – by G Subba Rao & P N Roy Chowdhury