which is best book ?

Hi Saleem,

There are a few books in the market, but many of them are compilations of old papers. It is better to prepare from online resources. Do check out Cracku's tests and products at the following links:

https://cracku.in/railways/rrb-2016-mocks

https://cracku.in/railways/rrb-previous-papers

https://cracku.in/railways/pricing

https://cracku.in/railways/quotient