A: The Understanding Post Processing guide was created when CS4 was still fairly new. When you read through the guide, you will notice that it is not a basic guide on how to use Photoshop and Lightroom. The content focuses mainly on a post-processing technique Mitchell uses to enhance images. There is actually not a lot of difference between the editing tools used in CS4 compared to the latest versions of Photoshop and Lightroom. That is why the techniques are still applicable regardless if the customer is using CS4 or the latest version.