hello aspirant,

rather than depends on book you should focus on practicing and increase the speed of solving problems. however gk questions plays a vital role in ssc as it is only 1 hour exam and if you solve about 20 gk correctly than you score will increase. gk, english, reasoning are the scoring subjects in ssc cgl. however rs agarbal is good for practicing. you can reffer bankers adda for gk. solve almost 10 years previous years questions also.