The book presents a novel approach for studying optimal experimental designs. The functional approach consists of representing support points of the designs by Taylor series. It is thoroughly explained for many linear and nonlinear regression models popular in practice including polynomial, trigonometrical, rational, and exponential models. Using the tables of coefficients of these series included in the book, a reader can construct optimal designs for specific models by hand. The book is suitable for researchers in statistics and especially in experimental design theory as well as to students and practitioners with a good mathematical background. Viatcheslav B. Melas is Professor of Statistics and Numerical Analysis at the St. Petersburg State University and the author of more than one hundred scientific articles and four books. He is an Associate Editor of the Journal of Statistical Planning and Inference and Co-Chair of the organizing committee of the 1st-5th St. Petersburg Workshops on Simulation (1994, 1996, 1998, 2001 and 2005).