Operation Research by Hamdy and Taha is good one.I used for the last year engineering.Its quite old one but covers major concepts.There is another one online book by Cornell professor, I will give the link in day or two.What topics of OR are you looking at?
Yeshwantpur
There are 10 kinds of people in this world. Those that understand binary get this tiny ad:
a bit of art, as a gift, that will fit in a stocking