The aim of this paper is to illustrate the underlying concepts and characteristics of hybrid warfare – a new type of modern warfare utilising unconventional methods and “proxy wars” which involve national minorities, terrorist groups and local communities. The paper also describes the current capabilities of states to engage in new warfare without declaring war while using all resources available, and identifies the advanced disinformation and propaganda mechanisms employed to achieve political objectives. The paper further provides a background to the outbreak of war in Ukraine by highlighting the causes and consequences of Russia's preparing for and launching the invasion of a European country in contravention of all international laws and agreements. The subject is dealt with comprehensively, from the annexation of Crimea to the destabilisation of south-eastern Ukraine by separatist military groups.