This predates the “For Dummies” books, and although it focuses on VWs, it’s also a primer on how all the systems in a gasoline-powered car work, how to maintain them, how to diagnose trouble and how to fix it. It’s written as if your Uncle Joe was coaching you, and the diagrams (and comics) are hand-drawn in Robert Crumb style. I learned a lot from it when I was in my 20s, and the book is still in print via Amazon here.
Even if you don’t own an old VW, get a copy and read it just for fun, enjoy the illustrations, and pass it on to your favorite teenage greasemonkey like I did. (It’s the perfect Christmas gift for someone with a VW, an adjustable wrench, a hammer and a couple of screwdrivers.)
Oh, and click on the image to see the big picture.