I found this book incredibly useful for research, and as one of the main sources of information for a law competition I participated in.
The information is presented in a clear manner, yet it encompases a large range of international law theory. On top of that it includes real life examples within the text, but in a format, that they can be skipped over if neccesary.
The book was a great guide to international law jurisprudence, pointing me in the right direction in every case.
This book is great either as an introduction to international law, or as a reference book.
I think its an all around must-have.