It returns the physical path of the file or directory from the virtual path. As we setup a site in a remote server we don't have access to the server root path of our site in case of shared hosting. As our site is stored inside a particular folder of the server and by browser or by ftp access we can't move upward to wards the root of the server so it is not possible to get the physical path of any directory or file. Some of the objects like FileSystemObject requires physical path to handle various file and directory related commands. So here we can convert a virtual address of path to physical path by using Server MapPath method.