OS X Installer

I keep reading articles about how to make a bootable drive in Lion and Mountain Lion. The articles keep pointing me to an installer in the applications folder. However, I cannot fint that installer. Can anyone help?

If you've already installed Lion or Mountain Lion, the installer has been deleted - it's removed as part of the install process.

So why do these articles keep suggesting that you look for something that is not there?

So is there anyway of making this bootable device?

Because each of the articles, if they are written properly, all note that you need to create the bootable copy before you upgrade.

If you want to make one now, you'll need to re-download Lion or Mountain Lion.

Ok. Thank you.