This is a general presentation of the book. The central thesis of the book is that the law of neutrality remains relevant in contemporary international law because of in an armed conflict, third non-participating States do not remain unaffected. There is a presentation of the basic argument in each chapter.

The relation between neutrality and the use of force is better to be kept within the law of armed conflict rather that the law on the use of force between States. This means that the right of self-defence cannot be the indispensable legal basis for the use of force between belligerents and neutrals. On the contrary it appears that neutral due diligence has been relied on as a basis to expand the scope of the right of self-defence. The latter is admissible as the basis for resort to force only in the case of resistance of a neutral State to repel belligerent violation of its territory or by a belligerent that fully complies with its duties under the law of neutrality.

A presentation of the concluding remarks and main submissions on the issues discussed in Chapters 1 to 6 of the book.

The debate on the compatibility of neutrality with collective security appears to have occupied scholars in the interwar period but not after the end of World War II. However, it remains relevant. Neutrality defers to collective security only if the Charter mechanism works effectively. Even then, however, neutrality is admissible if it does not subvert collective action authorized by the Security Council or the General Assembly under the Uniting-for-Peace resolution.

The law of neutrality is not obsolete. Its validity subsists despite the prohibition of the use of force,the advent of collective security and the violations of the rights of neutrals during the two world wars. The sources of the law are customary laws and treaties. Customary law of neutrality is based on State practice mainly in the form of national military manuals. It is applicable in the event of an international armed conflict irrespective of the existence of a formal state of war and irrespective of the scale and extent of th conflict. Neutrality has withstood the challenge of collective security and the prohibition of the use of force both in the interwar years and after World War II. The gross violations of the rights of neutrals during World Wars I and II have been justified as reprisals or countermeasures; this is a further confirmation that beligerent practice at the time constituted a deviation from the law rather than a change or demise of the law of neutrality.

The aplication of the law of neutrality in a civil war setting was contingent upon the recognition of belligerency of the rebels. However, the experience of the Spanish Civil war with the ill-fated policy of non-intervention in favour of either side in the conflict has established the inadmissibility of neutrality in non-international armed conflicts. Thus, neutrality is not applied as a matter of principle and by virtue of the rule that in the event of a civil war, assistance is permissible to the government but not to the rebels.

The law of neutrality introduces a concomitant set of rights and obligations between belligerents and neutrals. The law as it has settled at the turn of the twentieth century has remained the same in relation to its basic principles, and it has easily adapted to the evolution of the law of the sea, globalized trade and arms technology. The intrusiveness of belligerent practice in the form of exclusion zones, navicerts and distance blockade has become part of the law provided that it does not deviate from the humanitarian law of armed conflict. Moreover, the four Geneva Conventions and the First Additional Protocol admit a humanitarian role for neutral States.

Cyberspace may constitute either the exclusive area of operations or a means of conduct of hostilities in an otherwise conventional armed conflict. The basic text concerning the rules applicable in cyber warfare is the Tallinn Manual 2.0, a 'soft law' text that is not generally followed by the few States that include cyber warfare in their military manuals. However, the relevance and applicability of the law of neutrality in cyber conflict is not disputed. The proposed legal framework is in principle premised on the Hague Conventions V and XIII, though the particularities of cyberspace as a domain have admitted substantive deviations with respect to inviolability of neutral territory and neutral due diligence.