The law of treaties 
As we have seen in Chapter 2 , treaties are one of the most important - if not the 
most important - sources of international law.This need for certainty and 
clarity is the primary reason why the International Law Commission has made 
great efforts to produce a code of treaty law that itself can be formalised in a multi-
lateral treaty.In addi-
tion, it should be appreciated that the law of treaties is one of the least 'political' 
areas of international law, although one does not have to search long to fi nd various 
academic theories about how treaties should work.There are rules dealing with 
entry into force, termination, interpretation, reservations (being exceptions to spe-
cifi c obligations in a treaty) and the relationship of treaty law to custom.It is not 
surprising, therefore, that international law should have developed a specifi c set of 
rules whose sole purpose is to regulate the creation, operation and termination of 
these legally binding instruments.