This book deals with the statistical analysis of time series and covers situations that do not fit into the framework of stationary time series, as described in classic books by Box and Jenkins, Brockwell and Davis and others. Estimators and their properties are presented for regression parameters of regression models describing linearly or nonlineary the mean and the covariance functions of general time series. Using these models, a cohesive theory and method of predictions of time series are developed. The methods are useful for all applications where trend and oscillations of time correlated data should be carefully modeled, e.g., ecology, econometrics, and finance series. The book assumes a good knowledge of the basis of linear models and time series.