I needed this for my studies, I had trouble with the delivery, but after that was sorted it was fine! It's such an easy book and although some of it is confusing to grasp (mainly because I didn't understand the topic), it helped with the definitions in the back! If you need it for you course, definitely get it!
I needed this for my course in IR. My brother also uses it while studying Criminology. It is a fantastic book. Collins does not cease to amaze. I recommend this book to every student doing IR or IR related subjects, War studies, etc. It provides a fantastic insight in how international security works.