Dear Student,

You can use the following books for making your word power strong:

McGraw-Hill Essential ESL Dictionary

English Vocabulary in Use Series

Oxford Picture Dictionary

504 Absolutely Essential Words

NTC Vocabulary Builders

And best books for GK are:

Lucent's General Knowledge Book 2018. ...

Manorama Yearbook 2018. ...

General Study Paper-I. ...

General Study Manual Paper-I. ...

Objective General Knowledge.