This book intends to make NI more accessible and viable, especially as a critical device for better understanding contemporary politics. The purpose is to refresh the debate on NI and to explore this fascinating concept, appreciating its multifaceted and malleable nature. Throughout time, NI has been presented as an ambiguous but obstinate concept in politics, political discourse, and theoretical elaboration. NI has constantly resurfaced, and many designate themselves as its protectors. Its increasing relevance, pertinence and recurrence make it clear that it can no longer be ignored in political analysis.