I was already a student in Zaragoza in 1906, when the news spread: the new professor of Rational Mechanics has arrived, but he is a boy! A boy, certainly, because of his age, but a great gentleman because of his distinction and his culture; a boy who spoke perfectly all the learned languages and knew the history and literature of all countries, a boy who handled elliptic functions with the same ease as our old professors handled trigonometry.

...with true mastery of the various theories about radiation that have been established by Maxwell, Jeans, Lorentz, Planck and other scholars, laying down the principles of Statistical Mechanics, which serves wonderfully to be applied to theories of electromagnetism.

It was a position of high technical responsibility, since he had to try to comply with the political will of the Commonwealth to make the telephone reach all corners of Catalan territory. ... During his tenure, the Catalan telephone network notably expanded its services, transforming the telephone map of Catalonia.

I have discovered an extraordinary man: Terradas.

Terradas had an extraordinary love of knowledge and erudition, and anecdotes abound of his learning, even while he lived. For example, referring to Terradas' civil engineering examination, the architect Joan Bergós ... related that his friend, who was very knowledgeable about architecture, confided in him that he had "not dared to study it formally for fear that in the Advanced School he would lose his passion for architecture, the first of the arts. Bergós added that in the architecture examination for the Civil Engineering School, when questioned in regard to 'Byzantine decadence mouldings', Terradas was able to draw these without hesitation, to the total stupefaction of the Examining Board.

Under the Catalan Commonwealth, he had the opportunity to carry out his multiple activities in the organisation of the Institut d'Estudis Catalans, and in the construction of the telephone network, of the secondary railways ... And seeing in the call of the first dictatorship the possibility of working for Spain, he sacrificed his personal opinions to work together with other distinguished comrades of ours, within the radius of his possibilities; and the same he would have done under any political regime oriented towards the opposite fundamental view.

Terradas was very active in his years in Argentina. At the University of Buenos Aires he gave courses on mathematics and engineering; at the National University of La Plata, he was associated with the Astronomical Observatory and participated in the measurement of a meridian arc extending from the extreme north of Argentine to the south, directing the hydrographical part of the project (specifically, the determination of the mean height of the sea along the Atlantic coastline). His activities also included aeronautics. At the University of Buenos Aires, in 1940, he gave a course on theoretical aeronautics; at the National University of La Plata, he set up a group to study problems of aviation engineering, and gave courses and seminars on elasticity theory, aerodynamics and technical aviation problems (among them the construction of landing strips). Indeed, one of the few articles that he published in Argentina was on aeronautics. This work, on aircraft propellers, originated in a conference given at the National University of La Plata on the 24th June 1937, and eventually came to form part of his course on aeronautics.

For a long period of time his friends in Argentina tried to recover him, without success, for what he called "his second country." These efforts involved an influential group of scientists, research technologists and institutions which at the time were at the forefront of Argentina's research movement.

It is common that professors with extensive knowledge and great erudition in a subject do not know how to limit their exposition and mix major and secondary questions. On the contrary, D Esteban Terradas, who in Statistics, as in any other subject he explained, had a previous preparation in which he had exhausted the bibliographic sources, had not because of this lost the most precious pedagogical conditions of making his disciples clearly see the main paths, distinguishing them from the minor paths, and making them arrive and stop at the plateaus that allow a perfect contemplation of the scientific landscape that he had proposed to capture.

We are today convinced that our principal mission is not teaching in the archaic sense; rather, our fundamental duty is the study and the advance of science. We represent the culture of the homeland, and decorum and duty make it imperative that study becomes our central occupation; the time is long gone when didactic quality was measured in terms of the meticulousness with which a teacher of mathematics made a transformation or progressed from one formula to another. Today ... the quality of teaching is measured according to the ideas of the teachers and how these reflect thinking in the great cultural centres, as also by the nature of the problems that an intelligent student is capable of resolving.