Because of his extraordinary accomplishments, Professor Takács is one of the most celebrated contemporary probabilists. He has published over 200 papers and books, many of which have had a huge impact on the contemporary theory of probability and stochastic processes. His numerous works are yet to be explored. Although some people view Takács as a queueing theorist, it is just one of many areas of his remarkable influence. This opinion about him is also because queueing theory (or, as they say, just queueing) has become so overwhelmingly popular, and because Takács is indisputably one of the greatest contributors to the theory who ever lived. This may outshine his other contributions to the theory of probability, stochastic processes, combinatorial analysis, and even physics. For instance, it is not widely known that Takács was the first to introduce and study semi-Markov processes in the early fifties and which he had been using even before 1954, perhaps one of the most extraordinary achievements in the theory of stochastic processes in the second
half of the twentieth century.