... passed away when he was a few years old. His childhood was spent in the Bohemian atmosphere of his grandparents' house.

... every day he crisscrossed the city starting early in the morning the engineering courses; then teaching mathematics at ENI, and then until 10 pm studying mathematics; not only that: he decided to finish engineering in only 4 years so he had an accelerated pace.

This paper contains the main results of a Doctoral Thesis developed by the author under the guidance of Prof N E Steenrod and submitted to Princeton University in 1960.

The work of Sam Gitler is one of the more remarkable oeuvres in Mexican science in the XX century. Sam Gitler together with José Adem founded the modern Mexican mathematical school in algebraic topology, and maintained the highest standards in mathematical research in Mexico during decades in which, with no internet and repeated severe economical crisis, the isolation was considerable. Both were the founding fathers of the Department of Mathematics at the Centre of Research and Advanced Studies (Centro de Investigación y de Estudios Avanzados del IPN-Cinvestav), one of the most important mathematics departments in Latin America. While he published in many international journals of the highest regard, it is notable that most of his papers appeared in the Boletín de la Sociedad Matemática Mexicana solidifying its prestige as a venue for topology, for this was the intellectual love of Gitler's life: algebraic topology.

One of the problems that Gitler attacked with lucidly (together with José Adem and other collaborators) was the celebrated immersion problem. This problem asks whether projective geometries with points at infinity in any dimension (Brunelleschi (1404-1472), Kepler, Desargues (1591-1661), Monge, Chasles, Poncelet, etc.) can be immersed in ordinary Euclidean geometries. David Hilbert asked his student Werner Boy to show that it was impossible to find an immersion of the real projective space of dimension two $\mathbb{R}P^{2}$ into the classical Euclidean space $\mathbb{R}^{3}$ in 1901; Hilbert was very surprised as Boy found such an immersion. Another important result was Whitney's embedding theorem which states that every n-manifold admits an embedding into $\mathbb{R}^{2n-1}$, together with Boy's result, at the beginning of Gitler's career, no additional explicit immersions were known. ... Gitler published one paper per year devoted to the problem from 1963 to 1969.
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The opus magnum of Gitler was undoubtedly 'A Spectrum whose Cohomology is a certain Cyclic Module over the Steenrod Algebra' (Topology, 1972), in collaboration with Ed Brown; one of the most relevant works in algebraic topology of the twentieth century. It became a fundamental building block of modern homotopy theory going well beyond its original motivation.

It was in Oxford where I had the opportunity to meet the Gitler family and where I became another member of it, inasmuch as my friendship with Sam was extended from the beginning to Rachel and to his children Isidoro, Miriam, and Susy. With incredulity, I became aware that the doors of Sam's home were always open, and that it was a meeting place for several mathematicians and friends. The hospitality and cordiality with which me and my family were greeted by Rachel, her disposition to lodge us for several days and feed us splendidly, made me feel from the start as another member of that wonderful family, which I consider a fundamental part of my life.
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A distinctive quality of Sam's personality that I cannot omit is his exaggerated humility. Just as much in the clothes that he wears everyday, as in his personal manner, Sam does not carry on his shoulders the weight of the postures of the famous and conceited intellectual, or of the inaccessible man of success. On the contrary, he seems to pass, anxious not to be noticed. I recall the occasion in Oxford when, at tea time, Sam was taking about mathematics (for a change) to a group of students, myself included, when he hastily told us that he was going to travel to Mexico for about four days to receive a small recognition, and rapidly returned to the subject of mathematics. Several months later we learned that in that trip to Mexico, Sam received from the President of the country, The National Prize for the Sciences, which is the highest award possible for a Mexican Scientist.

The Mexican Government is struggling to regain control of an economic crisis that has unleashed a new round of record inflation, caused Mexicans to shun the peso and send their savings abroad, and stirred up labour discontent. Tonight, the Government announced an ''economic solidarity pact'' that includes sweeping tax increases and budget cuts designed to reduce the deficit.

In Rochester, he helped to build one of the most important groups in topology in the world.

In August 1993 a meeting was held in Cocoyoc, Mexico on the subject of Homotopy Theory and its Applications. There were many foreign participants in addition to a number of Mexican topologists. The main focus of the meeting was to highlight the current development of methods in homotopy theory, and how they can be applied to interesting problems involving classifying spaces, moduli spaces, representation theory, etc. The 16 papers in this volume testify to the diversity and activity in this area of mathematics.

This conference was partly held to celebrate Samuel Gitter's sixtieth birthday. ... Sam Gitler has contributed significantly to the development of mathematics in Mexico. He served as editor of the Boletín de la Sociedad Matemática Mexicana and ran many seminars which helped to educate young topologists in Mexico.

The purpose of this book is to introduce algebraic topology using the novel approach of homotopy theory, an approach with clear applications in algebraic geometry as understood by Lawson and Voevodsky. This method allows the authors to cover the material more efficiently than the more common method using homological algebra. The basic concepts of homotopy theory, such as fibrations and cofibrations, are used to construct singular homology and cohomology, as well as K-theory. Throughout the text many other fundamental concepts are introduced, including the construction of the characteristic classes of vector bundles. Although functors appear constantly throughout the text, no knowledge about category theory is expected from the reader. This book is intended for advanced undergraduates and graduate students with a basic knowledge of point set topology as well as group theory and can be used in a two semester course.

This carefully written text presents a new approach to a first course in algebraic topology. The main novelty is defining the homology groups of a (pointed path-connected) CW complex as the homotopy groups of its infinite symmetric product. Cohomology groups are defined as homotopy classes of maps into Eilenberg-Mac Lane spaces, which are defined as infinite symmetric products of Moore spaces. This differs dramatically from most standard texts by making no mention of singular or simplicial homology. ... The novel approach to homology used in this book can be disconcerting to one who is used to the standard treatment. ...
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In conclusion, this text has developed a truly new approach to introductory algebraic topology.

A conference on homotopy theory was held at San Miguel de Allende, México, on 3-6 December 2003. The conference covered several areas of current interest in the field ... The meeting was organised by the Department of Mathematics of the Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV) to celebrate Sam Gitler's seventieth birthday. It was extraordinary to see that the meeting was attended by many of his collaborators, colleagues, students, and friends. ...

In spite of the different important positions he has held, he has always been an enthusiastic topologist in his more than forty years of professional activity. Sam has written over forty papers as well as several books. All of them show a deep knowledge of topology and an acute point of view. Sam has been an active teacher. Several generations of mathematicians have benefitted from his expertise as well as from his immense generosity.

His mathematical work is one of the most notable within 20th century Mexican science. He was the founder of the modern Mexican mathematical school. He was able to sustain very high standards in mathematical research in Mexico for decades; if we consider that he achieved it at a time when there was no internet and during serious and repeated economic crises. His achievements are impressive given that Mexico's isolation in the field of mathematics was enormous. His contributions to mathematical knowledge materialised in nine collaborations in books, journals and conference proceedings, and in sixty-four articles published in specialised journals of the highest level, either individually or in collaboration with some of his colleagues.