The illegal war of aggression the Russian Federation has launched against Ukraine has created an opportunity to study and learn about civil defence and infrastructure protection in the conditions of a modern conventional war. The Lessons from Ukraine -project has gathered observations about the operation of the civil defence of Ukraine as well as the impact the war has had on the civilian population and infrastructure. Based on these observations the project has produced recommendations for the development of civil defence in Finland. The project has employed an exploratory approach. Its data sources comprise of expert interviews and a large volume of official and scientific documents as well as other reports. All document material is from public sources. Interviewees were instructed not to disclose any classified material and share only public information. Through content analysis a number of observations were produced, which are presented thematically in this report. Additionally, based on the observations as well as expert opinions, a number of recommendations regarding future research and development avenues were produced.