Appropriate for a one-semester course, this self-contained book is an introduction to nonparametric curve estimation theory. It may be used for teaching graduate students in statistics (in this case an intermediate statistical inference, on the level of the book by G. Casella and R. Berger (1990) "Statistical Inference", Brooks/Cole, is the prerequisite) as well as for diverse classes with students from other sciences including engineering, business, social, medical, and biology.