This book provides an up-to-date account of research in Approximation Theory and Complex Analysis, areas which are the subject of recent exciting developments.The level of presentation should be suitable for anyone with a good knowledge of analysis, including scientists with a mathematical background. The volume contains both research papers and surveys, presented by specialists in the field. The areas discussed are: Orthogonal Polynomials (with respect to classical and Sobolev inner products), Approximation in Several Complex Variables, Korovkin-type Theorems, Potential Theory, Ratinal Approximation and Linear Ordinary Differential Equations.