The CIMPA-UNESCO workshop ''Orthogonal Families and Semigroups in Analysis and Probability'' was held in 2006 in Mirida, Venezuela and was organized with the collaboration of three Venezuelian universities (UCV, USB, and ULA). The objective of the workshop was to present the modern theory of operator semigroups, related to polynomial orthogonal expansions. This theory comprises a vast body of knowledge and has interconnections with several other areas, including harmonic analysis, probability, random matrices, stochastic calculus, and control theory. The chapters in this volume originate from the lectures at this workshop and stress the interplay of all these domains.