Hi aspirant

If you are planning to prepare for GATE try to stick to some decent study materials.Don't buy random books or random publication books.

Once you start preparing from the good/error free material then you'll realise random publication books have lots of mistakes.

Its better to start preparing from right resource from the starting.

You can opt for MADE EASY PUBLICATION which is mostly preferred by GATE aspirants.Visit here to see the book list: https://madeeasypublications.org/BOOKS/GATE-BOOKS/4

ACE Engineering Study materials,GATE Academy Study materails.Visit here: http://www.aceengineeringpublications.com/

All the best.