In the last couple of days, I've found a couple of new (to me) resources for developing electronics and controls skills. The first, which has been making the rounds of the hacker/maker blogosphere, is Tony Kuphaldt's six volume Lessons in Electric Circuits, published by the Open Book Project. While not yet entirely complete, it's an excellent free complement to classics like the The Art of Electronics. It even has an entire volume of experiments, which should prove extremely useful to those just getting into electronics.
The second is something some of you will consider a bit more esoteric, Douglas Cooper's Practical Process Control. This book covers process control in the sense of computers (including microcontrollers) controlling things in the physical world, not in the sense of manufacturing process control. It's the intellectual glue that lets you go from merely making your project move to making to do things precisely in the physical world.