which books are important for Calcutta law BA.LLB entrance exam 2020
Actually you don't need to follow any one such particular book for your preparation.
I would suggest you to go through the entire syllabus and previous years question papers thoroughly which includes Maths, English, gk, logical reasoning.
Now, coming one by one. For English you can follow Wren and MArtin. For Mathematics, RD Sharma or NCERT is more than enough. For GK there are lots of books but i would suggest you to go through NCERT from 6-10 then Prasad.
"The Hindu" and "Indian Express" Editorial is must daily.