For International Law, you will find many good books. The most commonly available quality book is of J.G.Starke with the title 'Introduction to International Law'.

The conceptual side of the book is good, but I am afraid it is not updated or atleast its updated version is not available in Pakistan.

Nevertheless, its a good book and can be used as a starting point. Besides the books by Brownlie, who is a professor of International Law at Oxford and by one Tandon, who is an Indian author are also readily available and serve the purpose.

Please remember, to go through original documents for example you must read UN Charter, Universal Declaration of Human Rights 1948, Concept of Self Determination, Children Rights Convention and its protocols. There is no substitute of originality and it is the best way to increase knowledge in a credible manner for what you will get in books will be merely interpretations and views of different authors on the issues.

(Thanx Kamran Bahi)