Hello Aspirant ,

Different people will suggest you different books and some will even suggest you multiple books for one subject but you should choose quality over quantity and revise one book multiple time instead of reading multiple books one time .

Books for General studies are :

GS2 : Laksmikant for polity  and internet+Newspaper  for every other topics + 2nd ARC report.

GS3 : Indian Economy by sanjeev sharma or Ramesh singh and internet+Newspaper  for every other topics, Shankar IAS for Environment .

GS4 : Lexicon Ethics and  internet+Newspaper  for every other topics.

Hope this helps.