Besides a series of six articles on Lévy processes, Volume 38 of theSéminaire de Probabilités contains contributions whose topics rangefrom analysis of semi-groups to free probability, via martingaletheory, Wiener space and Brownian motion, Gaussian processes andmatrices, diffusions and their applications to PDEs. As do allprevious volumes of this series, it provides an overview on thecurrent state of the art in the research on stochastic processes.