For appearing in IPS you should be atleast 21 years and not more than 30 years of age.It is 33 years for SC/ST.The general candidates can attempt four times ,OBCs can attempt seven times and Sc/ST can appear any number of time.For IPS exam only Indian citizens are eligible.There are two papers for the prelims Paper 1 General Studies and Paper 2Optional Subject.For the main exam there are nine papers.Paper I Modern Indian Language Exam, Paper 2General English, Paper 3 Essay, Paper 4 General Studies, Paper 5 General Studies II, Paper 6 and 7Optional Subjects, Paper 8 and 9 Optional Subjects.. Books like competition review,NCERT Text books will be useful for the exam.Exams are generally conducted during the months of May and October.