The focus of research in this book is to develop the ways of making semiparametric/nonparametric techniques accessible to applied economists. While the papers by H. Bierens, J. Horowitz and R.C. Tiwari et al. deal with semiparametric techniques, the papers by Y. Hong and A. Pagan, J.S. Marron, G. Moschini et al., B. Raj and P.L. Siklos, D. Scott an H.P. Schmitz and A. Ullah deal with the nonparametric techniques. It is hoped that this issue will stimulate fruitful discussions and further research in the area of semiparametric and nonparametric econometrics.