As mathematicians we work on our research program, write up and publish our results, deliver lectures here and there disseminating our theorems and. once in a while, we attend the lectures and read the papers of our fellow mathematicians Some of us read a lot and some just rarely. But all of us have had that special experience of reading a paper (attending a lecture or having a mathematical discussion) which has been a personal turning point, perhaps because its techniques and elegance have illuminated ongoing work or be-cause it has led us to explore a whole new área of mathematics or because it has given us a new set of mathematical objectives. We all treasure those occasions and some of us, in the right context, even like to share them On the occasion of its centennial, the Real Sociedad Matemática Española asked the editors of the Revista Matemática Iberoamericana to contribute to the occasion by editing and publishing a commemorative issue of the journal. We decided to take the opportunity to ask distinguished mathematicians to write down thcir personal experiences as readers of research papers. We are convinced that such a collection of essays, written by a set of world-class researchers, will be interesting reading for mathematicians in general and that it will contribute to understanding the role of research journals in the development of mathematics We asked longtime friends of the Revista Matemática Iberoamericana, both authors and members of past and present editorial boards who have fostered and cared for Revista, to contribute with an essay about a paper -not necessarily the most important publication in the field- which, in one way or another, had a deep impact on their own mathematical carcers, espe-cially at its early stages, and giving the special reasons why "that particular publication" got their attention and affected their research We have been very pleased, even overwhelmed, with the response of the friends of the Revista to our cali. The reader will find among the articles in this book a surprisingly wide and rich variety of points of view, styles and approaches to this topic, all of which we appreciate greatly and have fully respected. Some are personal recollections with interesting anecdotes and charming stories about some well-known mathematician, while others present the state of the art of some specific ficld. Some papers are exquisitely technical while some others are perfect bedtime stories We offer our deepest thanks to all of the authors for sharing these con-tributions with all of us