That's a terrible book (and series) to learn from, the level of visual clutter on each page distracts from the actual task of learning anything. I had a copy of "Head First Design Patterns" and after only a few pages I thought my eyes were going to fall out.

I found Bruce Eckel's "Thinking In Java" useful back in day to learn OO programming and concepts. Much of what you learn is transferable to other languages.