Onésimo Díaz, a professor at the University of Navarra, presented in Pamplona his latest book, Posguerra. The first expansion of Opus Dei during the years 1939 and 1940. The event began with words of welcome from Pepa Escribano, of the bookshop Troa, to the presenter of the event, journalist Sonsoles Echavarren, and the author of the book, historian Onésimo Díaz. Echavarren emphasized the youthful and joyful atmosphere that could be felt at the students' residency program on Jenner Street in Madrid, where St. Josemaría Escrivá managed to create a family atmosphere thanks to the presence of his mother and sister.  

Taking these words from the journalist of the Diario de Navarra, Professor Díaz explained graphically through various anecdotes how the residents lived in the 1939-1940 academic year. He also clarified that the book "was not only a micro-history of the residency program Jenner and other Opus Dei centers, but an attempt to contextualize those facts in the Spanish post-war period and in the Second World War". According to the author, "when the Spanish Civil War ended, the founder of Opus Dei had only fourteen very young men and two newly incorporated women, and one mission statement who was barely ten years old". In a few months, these young men made 69 trips to 11 cities, managing to convince other young people that it was possible to seek holiness through study and the daily work .

Among the questions from the audience, Onésimo Díaz answered a question about the sources he had used. He said that the book was the main result of two years of research at file General of the Prelature of Opus Dei in Rome. Thanks to this work he has been able to show the life and vicissitudes of the founder and the people of that young institution of the Church after the war, since he was born in 1928. He has also consulted, among others, the file General Administration, the Royal Palace and the file General of the University of Navarra.

Postwar, published by RIALP, analyzes daily life in Jenner's residency program , and the first trips to Barcelona, Zaragoza and Valencia, Valladolid, Bilbao and San Sebastián, Granada, Salamanca, Murcia, Gijón and Oviedo during the two years following the war.