I can't think of a reference beyond Learning Perl, Perl Cookbook. I primarily use one or the other depending on what I need from the called program. Backticks will capture the STDOUT of the invoked program while system will return the exit status of the program. If I want the output, I use backticks, if all I need is the exit status, I use system. System does have one advantage over backticks in that you can spawn independant processes with system using the start command on windows, for example system("start $somepgm"). However, with backticks, start will not spawn an independant process. The calling program will wait until the called program exits. David Roths Win32 Perl Programming: The Standard Extenstions chapter 8 Processes, touches on this briefly but otherwise doesn't say much about it. I know that there are other ways of spawning processes, (fork, Win32::Spawn etc), but I like to keep things as simple as I can and backticks / system have worked for me so far.