The first thing you'll notice when you work with Photoshop CS2 is that the Layers palette has changed. The biggest change is that you can now select multiple layers. Command-click (Mac) or Control-click (Win) noncontiguous layers in the Layers palette to select them all. Or if layers are next to one another in the Layers palette, Shift-click the top and bottom layers you want to select. Now you know why Command/Control-clicking a layer no longer selects layer transparency, as I explained in an earlier post on Selecting the Contents of a Layer, the shortcut has been hijacked for this new multiple selection function.

Why would you want to select multiple layers? So that you can do things that affect them all, like moving them together or doing an Edit>Transform on them all. Selecting multiple layers also comes in handy when you want to align or distribute their contents using the settings on the Move tool's options bar, among many other things. The idea is that you don't have to permanently link layers together to perform a function on more than one layer. You can just select them all together temporarily.