GATE

There are very good books available for preparing GATE examination. But in order to have very good exposure and good understanding of all the concepts, you need to refer more than one kind of series. So based on that experience, below are my recommendations to crack the GATE examination.
For CSE students:
1 . GATE tutor 2018 Arihant publication
2. Trishnas: Computer Science and Information Technology
3. GATE 2018: Computer Science and Information Technology
For ECE students:
1. A Handbook on Electronics Engineering (highly recommended)
2. Arihants: GATE tutor 2018 Electronics and Communication Engineering
3*. Made Easy GATE 2018 Electronics Engineering
For EEE students:
1*. Made Easy: GATE 2018 Electrical Engineering
2*. Made Easy: A Handbook on Electrical Engineering (very useful)
3. Trishnas: GATE 2018 Electrical Engineering
For mechanical engineering:
1. Made Easy: GATE 2018 Mechanical Engineering
2*. Made Easy: A Handbook on Mechanical Engineering (useful one)
3. Arihants: GATE tutor 2018 Mechanical Engineering