One of the most recommended books for aspirants preparing for the UPSC exams is ‘Indian Polity’ by M. Laxmikanth. This book is appreciated for its comprehensive coverage of Indian political structures, governance, and constitutional provisions, which are crucial for the UPSC Civil Services Examination. Additionally, it is well-structured, encompassing both fundamental concepts and intricate details needed for Mains and Prelims. Many aspirants also suggest complementing this book with current affairs and relevant newspapers to keep their knowledge updated. It's essential to choose resources wisely for effective preparation.