Critical Reasoning

Hi,
I have two books for critical reasoning:
1) Powerscore GMAT Critical Reasoning Bible
2) Manhattan GMAT - Guide 6 - Critical Reasoning (4th Edition)

I'm rather weak in critical reasoning part, could anyone tell me which book is better to read? as I have time only for one of them;
or suggest me any other book that is the best for this part.
Thanks

Powerscore Critical reasoning, any day.

Thanks vineesh
do you have any idea for the best book to study for Reading Comprehension?

I am not sure, but as per https://www.beatthegmat.com/mba/store/books, Veritas Prep is a good source.

I did not use any books. Just OG practice and RC99 (not all, a few passages. They r too tough.)
Kaplan 800 is also a good source, but don't use it until you are ready to jump into 800 level problems. Practice helps. There is a main point chapter in CR Bible that will also help.