It is the second anniversary of Russia's attack on Ukraine. Ukraine is still resisting this Russian invasion with admirable vigour (and Western support). In addition to the territorial conquests on the territory of the former Soviet Union hoped for by Russian President and dictator Vladimir Putin, this war of aggression also marks the beginning of his policy aimed at destroying the North Atlantic Alliance and the European Union and transforming Europe into a collection of states without sovereignty. Politicians in Germany are slowly beginning to realise that this war represents a turning point.

The current SIRIUS issue brings together contributions from academia that attempt to draw lessons from the war. These lessons are of both a political-strategic and military nature.

• The article from Nataliya Bugayova, Kateryna Stepanenko and Frederick W. Kagan "Weakness is deadly - Why Putin attacked Ukraine and how the war must end" asks about the reasons for Putin's war of aggression and the lessons to be learnt from it with a view to the political-strategic dimension.
  
• Nico Lange consider in his contribution "How to beat Russia - lessons from the Ukrainian defence war" the military lessons learnt from the Russian war of aggression against Ukraine. He analyses the reasons for the largely successful Ukrainian resistance and comes to the conclusion that the NATO military can learn a great deal from Ukraine and that the experiences of the war must lead to the adaptation of their doctrines and political adjustments.
  
• The essay "A fragmented defence industry - Europe's strategic disadvantage ", from Paula Alvarez-CouceiroThe report deals with another political-strategic problem: the inability of the Europeans to shoulder a really substantial part of the military support for Ukraine.

Further brief analyses and interview:

• Sebastian Bruns and Heinz-Dieter Jopp: "The wet flank of the Russia-Ukraine war - lessons for modern naval warfare and the navy"
• Juliana Süß: "Space capacities in the Ukraine war"
• Markus Reisner: "The Kalashnikovs of the air - drone warfare in the Ukraine war"
• Joachim Krause: "Was it possible to foresee Russia's war against Ukraine?"
• Interview with David Domjahnexpert for blasting technology: "What do we know about the attacks on the Nord Stream pipelines in September 2022?"

After the Presentation of results more diverse international strategic studies and several Book reviews closes the booklet with a Obituary on Prof Dr Helga Haftendorn (1933-2023).

As usual, the entire current issue is available online under the Open Access licence via De Gruyter Verlag HERE freely available.