He is Professor of Contemporary History at the University of Zaragoza and a visiting professor at Central European University. Specialising in the history of 20th-century Spain, his work focuses on the Second Republic, the Spanish Civil War, anarchism, political violence and historical memory.

He is the author of an extensive body of work translated into several languages, including La Iglesia de Franco (2005), República y guerra civil (2007), Europa contra Europa, 1914-1945 (2011), España partida en dos (2013), Una violencia indómita. El siglo XX europeo (2020) and Franco (2025). He has been a visiting professor at several universities, a member of the Institute for Advanced Study in Princeton and historical adviser on Alejandro Amenábar’s Mientras dure la guerra (2019). He is a regular contributor to El País and received the Premio de las Letras Aragonesas in 2021.