hello sir, I AM THE BEGINER FOR THE PREPARATION FOR TH IAS EXAM...I WANT TO ASK HAW CAN I START THE PREPARATION FOR THIS EXAM.........FIRSTLY , I CANT DECIDE WHETHER WHICH PRELIUM OR MAINS I SHOULD BE FIRST STARTED.. AND SECONDLY ABOUT BOOKS ....LIKE FOR ECO. , GEO. , ......NOW I AM IN 3 RD YEAR.IN MECHANICAL ENG. .SO PLZ SEND ME ALL SUCH INFORMATION...