Javier and I were best friends. Through that friendship, we mutually influenced and enriched our lives in many respects. We started knowing each other when he invited me back in 1988 to read together John McCarthy's papers on circumscription. To that time I was working in mathematical logic, more precisely in model theory. So, that was something quite new to me. That is how I got into KR. I remember those days quite well: before Javier even applied to a PhD position, he knew what he wanted to do in research, namely introducing explicit temporal reasoning into the situation calculus. He also wanted to work with Ray Reiter. He was accepted as a PhD student in Toronto. We arrived in Toronto on the same day, in August 89. He was going as a PhD student, I was going as visiting professor to the UofT. I remember Javier had to work hard convincing Ray Reiter that his intended research subject was interesting and relevant. He managed to work on his own research subject. Javier's PhD thesis has been widely cited and explicit time in the situation calculus is something completely established. Back in Chile after his PhD he was able to produce some very nice and relevant papers; in spite of the fact that his work was not appreciated there. It was scientifically oriented and not "practical" enough for the kind of academic atmosphere offered by the School of Engineering at the Catholic University of Chile in which we were immersed. For this reason, the last years of his life in Chile were extremely hard. Fortunately he received the hospitality of people like Ray Reiter, Pat Doherty, Amilcar Sernadas, etc. so that he could spend some time abroad every year. Javier was a generous, supportive, courageous and influential person. He was also very original in his way of working, living and thinking, in general. He was extremely honest and serious in his academic activities. He could barely stand those colleagues who use to transform their academic activities into mainly commercial activities and permanent self-promotion. Those who use students as inexpensive labor force for their own projects instead of concentrating on their education and training. Those who trivialize teaching, research and the permanent ideals that support academia and scholarship. Javier was also a free thinker. He would not recognize any kind of authority that was not deserved. Under those circumstances, it was difficult for him to work in a vertical institution, in which authority usually is gained through hypocrisy, obscure political maneuvers and a pretended and self proclaimed closeness to the faith and the church. An institution where an unhealthy interleaving of academic and religious matters was prevalent, even at the extreme of not promoting to full professor someone who was considered to have broken a Catholic sacrament, independently of his/her academic merits, was not the right place for a free spirit. In spite of his sometimes rough interface, of a certain impulse to jump fast into conclusions about people, Javier had a permanent concern for other people and for the dignity of those who worked around and with him. In the last time of his life he had become extremely worried by the working conditions of the administrative and secretarial staff. They are treated as the lowest caste, defenseless against injustice and abuse. One has to admit that Javier's prompt characterizations of other people were often right and accurate. Even in those cases, he was always flexible and willing to modify them. My friend eventually decided to leave his country and took a position at Bell Labs in Murray Hill, in 2000. For similar reasons I established myself in Canada a few months later. Javier knew what he wanted in his academic life, and was able to reach his goals, without any compromises and without giving up his strong principles. He was lively, enthusiastic and had a strong sense of humor. We will all miss him too much.