In 1965 Belgian-born French mathematician Jacques Neveu (1932-2016) was in Berkeley teaching a course in modern probability theory. His time in the United States inspired generous gifts to the American Mathematical Society. "It is a great pleasure for me to contribute to the remarkable work done by the American Mathematical Society with the remembrance for all the marvellous contacts I have had with the American mathematical community," he wrote the American Mathematical Society in 2006.

We present a survey of some recent work done on the problem of existence of bounded invariant measure for positive contractions defined on $L^{1}$-spaces.

I met Jacques Neveu at a very special moment in the history of Parisian universities, 1969-71, where the only University of Paris with its headquarters at the Sorbonne gave birth to the thirteen universities that we know today. Jacques ... closely followed the painful and complex upheavals that accompanied the birth of the two French universities, Paris VI and Paris VII, which, with regard to mathematics, belonged to the old IHP, the Henri Poincaré Institute. Often, at the foot of the towers of Jussieu, we discussed the future that was open to us, our ability to act, to help guide it according to our ideal. At the time, the Mathematics Department of the University of Paris had a two-headed management, each of the two heads representing one of the two universities in the making, and I was, on François Bruhat's initiative, one of those two. At that time, my discussions with Jacques revolved around what would happen to this still planned university, to which Bruhat would devote ten years of his life. In principle, teachers were free to choose their university, but in practice the choice of the laboratory head determined that of his colleagues, and so Jacques, following R Fortet, found himself in Paris VI where, he told me, he was not happy; so, as soon as he could, he went to the École Polytechnique.

As a lecturer at the Paris Faculty of Sciences, Paris VI University and the École Polytechnique, he took great pleasure and care in his teaching, and he shared his passion with several generations of probabilists, scientists and engineers with varied vocations. His classes were always luminous, wonderfully compact, and full of that elegance that made his books get so many references today.

This is an excellent book by a brilliant mathematician, expertly and beautifully translated into English. As a text it is intended for study by advanced students (corresponding roughly to the first or second year of graduate work in probability or measure theory in the United States and Canada) and as a reference work for researchers. There is no doubt that it will succeed brilliantly in fulfilling these aims.

From the beginning of his career his impact on the mathematical community and the French school of probability is obvious and striking, at a time when applied mathematics and probability theory in particular are still gaining ground. The first seminars he conducted in Paris stimulated a whole generation of young probabilists, implicitly in tandem with Paul-André Meyer and the Strasbourg School. All along, he played a central role in the development of probability theory, especially through the working groups he led in a lively way. His research is one of the most beautiful pages of probability theory: Markov chains and processes, Gaussian processes, ergodic theory, potential theory, martingales, point measurements, random trees and branching processes. Beyond the fundamental aspects, he also contributed to the development of applications. In the field of stochastic networks, his founding works as well as the reading group he led on this subject at the end of the 70s, structured the French community. Subsequently, he contributed to the links with fundamental computing, combinatorics and statistical physics. He also founded the group "Modélisation Aléatoire et Statistique" of the Société de Mathématiques Appliquées et Industrielles [in 1991].

... we did not see each other anymore; it should have been the end of our friendship: chance decided otherwise. My wife owns a small family home in La Ripe, a hamlet of ten inhabitants above the Yonne, where we spent all our holidays. We did our shopping in Mailly-le-Château, on the other side of the Yonne. One day we meet Jacques and his wife, Monique, at the baker's! The Neveus had bought a beautiful property in this Burgundy village, three kilometres from us. A beautiful mansion, a beautiful flower garden terrace on the back overlooking the river and, on the other side of the street, a vegetable garden. In the living room, Jacques had installed a magnificent fireplace built to his plans, in which he liked to burn tree trunks of good size, for the great joy of his guests when the weather was cool. It was in this context that Jacques discovered a new passion. He had always liked to cook, and he cooked very well; he now cooked the vegetables and fruits of his own garden. Depending on the season, turning over the land, pruning trees or roses, preparing seedlings, harvesting strawberries or leeks, he was always at work! Difficult to leave this welcoming home without taking a jar of plum jam or jelly.

Other academics, scientists: some renowned archaeologists, physicists, curators of the Louvre Museum, chose to buy a second home in Mailly-le-Château and found themselves around the Neveus. This peaceful village, two hours from Paris, which for decades evoked angling in the Yonne or climbing on the cliffs of Saussois and was known around the world for high places for climbing became unknowingly the seat of a curious literary set where the quality of the cuisine of Jacques and Monique disputed with the richness of the conversation!

These happy days are a thing of the past. With the coming of age and the accumulating fatigue, Jacques had to call on a professional to execute the heavy work in his gardens. Their beautiful house in Mailly-le-Château was closed all year in 2015. Monique died of cancer and Jacques followed soon after her. A few days before his death, he called me to tell me he was in the hospital ...

His work in the Probability Laboratory at Jussieu and the Centre for Applied Mathematics at the École Polytechnique remains an example of clairvoyance, generosity and discernment. Friendly and considerate, of a great culture and sensitivity, his company was sought after. Like many of us, I have a very vivid memory of Jacques Neveu's quick intelligence, of his inexhaustible taste for rigour, for the elegance of his thought.