During the 20th. century, the number of States has considerably increased and science as well as technology have been in constant evalution. The scope of international law was dramatically enlarged, as shown by the developping activity of international organisations. These stricking transformations, (which are actually reading an end with the collaps of an international society dominated until a recent past by the rivality between two superpowers) does explain the successes which have been known by the codification of international law. In the future, which can be forseen through the role played by the United Nations during the Gulf War, one could expect the outcome of a permanent force under the control of the United Nations, the limitation of nuclear weapons and the entrancement of international justice and equity.