I was lucky to be born in the country and there spend my first sixteen years.

I did not like school very much and was not a brilliant student. My passion was drawing and painting, watercolours, my dream was to become a painter. Yet I remember one of the many mathematics teachers who made me understand the concept of algebra, which consists of calculating with an unknown x, and the large resulting simplification for solving arithmetic problems. But this teacher did not stay long. Another came, who no doubt loved mathematics, but apparently he liked even more the "Aigle " - the Aigle wine has indeed a good reputation.

During my last year at college, I was a victim of the 1918 flu, and the doctors ordered that, for my recovery, I had to miss school for several months. I think it was lucky, not only because I could indulge my passion for watercolour, but mostly because then I had to work alone, to catch up on what was done during my absence at school, and then I discovered that working only with the help of a book and sometimes the notes of a friend, you learn a lot better and in a much more profitable way than going to school.

It is interesting to observe that the family eventually moved into a set of apartments of the well-known Château de Beaulieu, in central Lausanne, which remained Georges de Rham's permanent address until the end of his life; thus '7, avenue des Bergières, Lausanne' became a familiar address to all his many mathematical friends all over the world, many of whom stayed at this address when they came to Lausanne (as evidenced by several letters).

At the Gymnasium, Maurice Millioud proposed that I make a comparative study between the 'Traité des passions de Descartes' and the 'Psychologie des sentiments de Ribot'. Benjamin Valloton asked me to give a talk on 'La Légende des siècles' Ⓣ by Victor Hugo. This work captivated me. And the lessons on Greek by Jean Franel were exciting.

I launched myself with passion and I've never regretted it.

... de Rham considered moral straightness, altruism and respect as the very reasons of Dumas' success in teaching.

... is divided into four chapters; the first gives a good summary with improvements of the theory of finite complexes and their homology; the second chapter discusses intersection theory of chains in a complex; the third chapter introduces the use of multiple integrals over chains in an $n$-dimensional variety using as integrands differential forms, and the fourth chapter gives several examples of complexes which have the same Betti numbers and the same torsion, but are not equivalent.

De Rham had a subtle charm which drew younger people to him immediately. In those early days at Princeton he would easily mingle with the boisterous postdocs, his exquisite manners contrasting amusingly with our rude ways.

In some sense the famous theorem that bears his name dominated his mathematical life, as indeed it dominates so much of the mathematical life of this whole century. When I met de Rham in 1949 at the Institute in Princeton he was lecturing on the Hodge theory in the context of his 'currents'. These are the natural extensions to manifolds of the distributions which had been introduced a few years earlier by Laurent Schwartz and of course it is only in this extended setting that both the de Rham theorem and the Hodge theory become especially complete. The original theorem of de Rham was most probably believed to be true by Poincaré and was certainly conjectured (and even used!) in 1928 by Élie Cartan. But in 1931 de Rham set out to give a rigorous proof. The technical problems were considerable at the time, as both the general theory of manifolds and the 'singular theory' were in their early formative stages.

The theorem is then a sort of topological form of the particle-wave equivalence of quantum mechanics, and the quest for 'truly' understanding these and analogous dualities has been one of the great motivating forces in the mathematics of the last fifty years.

Essentiality, linearity of thought and calmness made up the elegance of his lectures and seminars, where, according to Henri Cartan, he was able to "suggest a lot of things in few words." His approach to the audience was always full of benevolence and care. ... "Never forget that you must love your pupils", was his favourite advice to his assistants.

... de Rham had a subtle charm which drew younger people to him immediately. In those early days at Princeton he would easily mingle with the boisterous postdocs, his exquisite manners contrasting amusingly with our rude ways. He was always lean and one could feel the steel in his sinews, but he never boasted of his mountaineering exploits and it was only at second hand that the daredevil in him became apparent...

Tough as steel in his adherence to principle, resilient, placable, self-less and generous beyond the dictates of fashion, steadfast in friendship, but not at the price of reason, de Rham strides the world of mathematics a happy warrior.

... he did as much as any one man could do to bring mathematicians together, young and old, classical and modern, from the East and West. He found a special joy in the spectacle of younger colleagues adding to the old heritage, and did as much as he could to encourage them.

According to the testimonies of those who have known Georges de Rham, it seems hard to separate, in his personality and his public engagement, the loyal colleague from the generous friend, the passionate researcher from the fatherly teacher, the brilliant scientist from the brave alpinist. He regarded proving a theorem, delivering a lecture or reaching the top of a mountain as a personal endeavour, requiring a full involvement of the deepest and most precious faculties of the individual, in the name of some kind of transcendental beauty. On the occasion of the centenary of de Rham's birth, his former doctoral student Oscar Burlet remembers that he once explained to him: "For alpinism is not only a physical exercise, but it also a task for the mind, and it allows one to create a marvellous harmony between nature, soul and body." Climbing higher to attain a larger view could be considered as a metaphor for de Rham's constant attempt to advance in abstraction, to gain generality by looking at single problems and objects from above. The development set off by his first proof of the theorem bearing his name moved exactly in the direction of embracing specific questions in a more and more general framework. His scientific approach is based on the comparison of structures, which, unlike in the so-called 'abstract nonsense', should not be treated as empty buildings, but employed as containers that enable us to grasp different particular cases at the same time.

The courses, the books should only be suggestions and inspirations to work: a mathematician must judge on his own account, he must be critical and must not admit anything which he has not clearly recognized himself as well-founded.