This book is a follow up of "Theory of Optimal Designs" by K.R.Shah and Bikas K.Sinha published in this series. Unlike the previous book, this one covers a wide range of topics in both discrete and continuous optimal designs. The topics discussed include designs for regression models, covariates models, models with trend effects, and models with competition effects. An extensive study on a new optimality criterion is also presented. The prerequisites are a basic course in the design and analysis of experiments and some familiarity with the concepts of optimality criteria. Erkki P. Liski is Professor of Statistics at the University of Tampere in Finland. He has been head of various research projects on theory and applications of statistics with the Academy of Finland. Nripes K. Mandal is Professor of Statistics at Calcutta University in India. He is closely associated with all academic activities of the Calcutta Statistical Association. Kirti R. Shah is Professor of Statistics at the University of Waterloo in Canada. He is currently the president of the International Indian Statistical Association. Bikas K. Sinha is Professor of Statistics at the Indian Statistical Institute in Calcutta, India. He has served on the editorial board of a number of international statistical journals.