This work is the result of a high-level Spanish-Hungarian scientific collaboration. It is proof that we have common themes, values and interests. Several decades of the 20th century have been a period of great burden for the entire European continent. In most countries, totalitarian regimes have taken over the state in the long term and this was no different in Hungary either. For forty years, between 1949 and 1989, our country, then officially known as the Hungarian People’s Republic, was governed by a communist regime. Soviet-type dictatorships in the central and eastern half of Europe caused the economic backwardness of our region, including Hungary, and also a social backwardness compared to the western half of the continent. I think it is important to see clearly what led to this political system and how Hungarians and millions of citizens of other nationalities around the world experienced it. According to data provided by countries with this state system, communism claimed nearly 100 million victims worldwide. It is our duty to know and share their story. The Spanish contribution to this work and the excellent professional relationship established with the Hungarian National Remembrance Commission are especially commendable. I thank Professor José Luis Orella Martínez and the CEU San Pablo University for not sparing resources to take another step in bringing our country closer to the Spanish citizens interested in it, and for doing so at a time when We hold the Presidency of the European Union in 2024. I congratulate you on your excellent work and wish you much success for future cooperation!