PDF Layers in Apple Preview?

So I'm starting to get a lot of PDFs that have multiple layers, that is, different levels of text and pictures which can be turned on and off. The main benefit is that you can turn off, say, the pictures layer to make a document more printer friendly.

However, there are a few PDFs I've gotten that just look like a big mess with all the layers turned on. There's a little annotation in the PDFs I've seen like this that say that there are layers in the document, so I know it's not a bad PDF. Adobe Reader can handle these layers, but I can't seem to find a way to get Apple Preview (Leopard version) to acknowledge it or to find a way to turn them on and off. Is there any way to get it to do so? Are there any plans in the future to support it? Or am I stuck using Adobe for those?

Sorry, I didn't mean to sound ignorant and I didn't expect a harsh response.

I take it from your response that layered PDFs contain non-standard PDF code that Apple Preview does not support. I did not realize that was an issue. Preview has been able to flawlessly view every JPEG image I've thrown at it, for instance, so I naturally assumed it was able to handle every PDF as well. I don't have another program to view JPEGs, so I didn't think I needed to have another to view PDFs.

I don't deal with PDFs often, but Preview has worked for every one up till now. I like using one program for all my needs (it's simple that way). It's a pity that publishers don't adhere to standards so that their PDF only works with a handful of programs.

Even so, I do hope that Preview adds support for layers in the future, as it seems like a good idea.