This package contains a library for the single index model estimation with shape and smoothness constraints on the link function. To install the package, use the command R CMD INSTALL simest. All the code is written by me. The code implemented is not still optimal. Please, report the bugs, any comments and suggestions to us by e-mail. Please, also let me know about any applications or use of the package. Arun Kumar Kuchibhotla Rohit Kumar Patra