Just a warning: The Google book PDF is Adobe DRM'ed. Which puts a bit of a bumper on downloading it on Linux.

Well that's a shame.

Are there any alternatives, especially in a format other than PDF?

I understand that layout for programming books is difficult, but I don't want to put a PDF on my Kindle and have to choose between zooming way out or flipping up and down the page.

I don't have a download EPUB options, so it seems Adobe DRM'ed PDF is the only way, apart from reading it online.

Wolfenstein 3D was released in 1992. How much information in this book would actually still be relevant in todays game dev world?

That's absolutely not the point of this series.

However, seeing creative solutions to a problem usually helps me come up with my own creative solutions to similar problems, even if it's down a different path.

The first ~50 pages are free on google books, you can see that it goes into great detail about things like VGA and how the bus worked. So it's not very relevant for today, but it's fun; at least for old (36) people like me.