The chapter describes various aspects of the engineer's life. It may be natural that Massera showed an innate talent for mathematics and that he made his way into the study of it in an original way. Perhaps it should also not be surprising that he presented himself as a socially restless young student with excellent grades. The most interesting point here, the one that can almost be considered a revelation, is Massera's "class origin," to use Marxist terminology. Massera's father, José Pedro Massera Martínez, was a Batllista intellectual, professor of philosophy and a philosopher who became a senator of the Republic for the Colorado Party (1927-1933) and who is remembered today in the Montevideo gazetteer, in a square that bears his name, located on the capital's boulevard at the height of Miguel Barreiro, in the Pocitos area. José Luis's mother, Ema Lerena Joanicó, came from educated and wealthy families, traditional in Uruguay. This chapter, perhaps the most difficult to elaborate due to its remoteness in time and the lack of documentation, was assigned to Roberto García Ferreíra, a young historian who presented himself to the aforementioned call.

It is the story of one of Massera's most significant contributions to Uruguay; because of how difficult it was to build a scientific school, because of how early it was in historical terms and because of the success achieved. The most relevant fact of this period was the creation of the Institute of Mathematics and Statistics (IME) of the Faculty of Engineering, in 1942. This chapter was requested from Marta Inchausti, who after her contribution in the offprint of Volume 7 of Mathematics Publications of Uruguay, has become a reference in this subject.

The challenge of "popularising" Massera's mathematical contributions was taken up and focused on two lines of his work: the theory of asymptotic stability of motion (to which one of Massera's most famous papers published in the Annals of Mathematics in 1949 is devoted), and the study of differential equations in a Banach space, which is developed in the book by Massera and J J Schäffer Academic Press (1966). The mathematicians Jorge Lewowicz (considered one of Massera's first students), José Vieitez and Roberto Markarian took on the challenge. The reader has the last word on the success of such an arduous task.

Militancy was another of the central activities of the engineer over the years. He himself, on the occasion of receiving the Mexico Prize for Science and Technology (1997), expressed his gradual abandonment of mathematical research due to the occupation required by his party and parliamentary tasks. Fortunately, time and the vocation for the historical truth of our people have allowed Uruguay to produce, inside and outside its borders, researchers concerned with the recent history of the country. Among them, we have the participation of Gerardo Leibner, a Uruguayan historian based in Israel, specialist in the history of the PCU, author of the chapter.

This chapter covers practically the same period of time as the previous chapter. At the same time that the figure of Massera, due to his recognition as a scientific and university personality, was called to play a prominent role in the great spheres of citizen action (the "mass fronts" in the communist jargon), he began his work in the Engineering Student Centre, in solidarity committees with the Spanish Republic first and later with anti-Nazi solidarity action, in the co-government of the Faculty of Engineering and in parliament as a deputy. Massera also participated in the creation of the political coalition "Frente Izquierda de Liberación" (Fidel) in the sixties, and later the political coalition Broad Front. The task of recounting and reconstructing these activities was entrusted to the young historians Mauricio Bruno and Nicolás Duffau, selected in the aforementioned public call.

The article "The dignity of prisoners" by Eduardo Platero, published in "El Municipal"" in homage to Massera after his death on 9 September 2002, makes it clear that the personal characteristics of the engineer led him to play a very prominent role even during his time in prison, most of the time in the Libertad Prison. We are faced here with a unique situation. The strict isolation between two worlds generated during the dictatorship, made that of the prisoners take on a nature of their own. The prisoners created their own rules, their language and, naturally, their organisations and their forms of struggle, given that they were men whose maxim was to transform the world. Some books and films have been appearing about the world of Uruguayan political prisons, which show, among other things, things, the differences in the ways of life "inside" and "outside", various psychological aspects and the assumptions within the prison. These aspects added to the high shared nature of the Penal de Libertad suggested searching for the authors of this chapter among those who were personally close to Massera during his imprisonment. Thus we invited Néster Bardacosta to collaborate, a then young political prisoner of Juan Lacaze, who shared a cell with the Engineer for several of those years, and Eduardo Platero, a former political prisoner, prominent union leader and history teacher. Both recount from their memory how Massera went through this period. As this chapter is the least "professional", we believe that its inclusion is a vital contribution to the character we honour because it helps us get to know him in extreme situations and, at the same time, helps to consolidate the memory of the harsh years of the dictatorship. The third part of this chapter is a brief text in which Elvio Accinelli and Roberto Markarian (who together with Massera constituted a trio of imprisoned mathematicians) try to reconstruct, from another time and space (the year 1996), that climate of the Libertad Prison, and how Massera's personality developed and radiated in that context. The first appendix supplements this chapter.

This chapter describes the events that took place simultaneously with those of the previous one, but they take place in very different places and very far away: outside the Libertad Prison, with no other border than the entire world (mathematicians would say "in the complement of the Libertad Prison"). Chronologically, it begins with Massera's arrest in October 1975 and ends with his release in March 1984. Massera's uniqueness as a political prisoner also made his release campaign unique, which justifies a separate treatment. A large and persistent network of exiled Uruguayans promoted solidarity with Uruguay and its political prisoners in general in every possible way. Entire communities of exiles achieved, working like the drop that corrodes the rock, declarations from social groups, universities and parliaments of other countries, becoming an audible clamour, even within the Libertad Prison. But the international campaign for Massera's release took on a vast dimension. The distinguished communist scientist imprisoned for his ideas raised dozens of declarations, awards and even offers of contracts to work abroad in many parts of the world. The historian Mario Mazzeo (also selected in the public call) documents part of this immense activity, based on the material preserved in the General Archive of the University, the result of the tireless activity, among many others, of Martha Valentini (Massera's second wife) and his daughter Moriana Hernández, exiled in Mexico during the dictatorship.

Massera's release in March 1984 marks the beginning of a new stage in his career. After the captivity, Massera reflected like others on the end of the dictatorship, the reconstruction of the University and the scientific system. The creation of PEDECIBA and the Faculty of Sciences correspond to this period, as well as the resurgence of scientific activity in the Faculty of Engineering, the engineer's primary field of action. At that time, Massera was a demigod for many: he added the condition of being one of the most outstanding scientists in the country in all his eras, with his dignified attitude as a resistant political prisoner and victorious communist leader, two auras whose combination produced an impressive effect. He was also a reference for many young people who had been deprived of their leaders due to the generational break caused by the dictatorship. The authors of this chapter, the young historians Evana Alfonso and Álvaro Sosa, were selected in the call. The second appendix complements this chapter.

Massera, an intellectual par excellence, contributed with numerous articles and books, to the development of mathematics, but also to the fields of everyday politics, political strategy and Marxist philosophy, both in the most theoretical fields and in those of popularisation. Covering and documenting all of Massera's written work (including, for example, parliamentary debates) is a task that is beyond the scope of this book. Two prestigious social scientists were invited to collaborate: Professor Juan Fló, who made a brief sketch of Massera's contributions to philosophy, and Professor Álvaro Rico, who dedicated himself to the engineer's contributions to the social sciences. The third appendix complements this chapter.

In the development of the work, the possibility of including other materials that broaden the vision of the book arose. The first appendix is a summary of Massera's activity registered through the National Directorate of Investigation and Intelligence of the Ministry of the Interior, whose files were opened to some historians in this last period of government. One of them is Roberto García Ferreira. editor of the first chapter, who was asked for this contribution, which demonstrates the depth and systematisation of the political persecution of Massera before and after the dictatorship. The second appendix arose at the request of Evana Alfonso and Álvaro Sosa to integrate into the book a brief review of Massera's activity within the PCU in the post-dictatorship period and, mainly, his position in the complex moments of the disintegration of the Soviet Union and the block of socialist countries, with the consequences, repercussions and discussions that were generated in this historical period within the Communist Party. The document presented incorporates comments by Aníbal Toledo. It is clear that these contributions do not exhaust these highly complex issues. Finally, the third appendix briefly reviews an emblematic book by Massera, the Manual to understand who empties the fortnightly envelope, in which he explains the nature of surplus value with the aim of disseminating this notion. This appendix was written by economist Daniel Olesker.

The book we are presenting probably has innumerable omissions: many unintentional and others we were unable to document. It is part of the task of writing: you have to choose at all times. However, we want to highlight some shortcomings and, in some sense, justify them. The exile campaign undoubtedly omits the collaboration of many actors, but in particular it does not describe in detail the important work carried out by exiled mathematicians in Venezuela, due to the lack of written information and the pressure of deadlines for the delivery of the manuscript. This last point also meant that Massera's communist education work was not reported, but the difficulty was the opposite: Massera's prolific written production in the PCU media, especially in the journal Estudios, as well as in the communist press. (Justicia, El Popular, among others) exceeded our possibilities. We give then our apologies.

In the various stages of genesis and preparation of this book we have received contributions, many of them decisive, that we want to thank. Rodolfo Gambini was the promoter of this work and encouraged its realisation beyond the difficulties that arose. Enrique Lessa, who succeeded him in the direction of PEDECIBA, continued with this line of support. Alcides Beretta Curi contributed his experiences as the author of the first book in this series, contributed to the selection of the authors and participated in the general design of the work. Marcelo Cerminara read some parts of the book providing valuable suggestions. Ana María Ferrari carefully read an almost final version of the book and made important corrections. Various officials from the Faculty of Engineering, particularly from its Library, collaborated in reviewing information on Massera's activity and work. The union leader Arubal Toledo carried out, at the request of the editors, a detailed reading of the handout on the history of the PCU after the dictatorship, providing valuable comments, which were included. Marta Valentini provided us with all kinds of information and much of the graphic material, and she encouraged the project at all times. We would like to offer special thanks to Vania Markarian, who in some key periods of the book's development worked alongside the editorial team, facilitated and guided the use of the General Archive of the University of the Republic, a vital documentation centre for many of the chapters of the book, in addition to collaborating with the general design of the book.