Knowledge is power..... and all that! I agree there's no substitute for creativity but you have to have a decent understanding of the technology/processes/equipment surely? A colleague of mine recently asked me why when he was taking long exposures of moving water were the pictures over-exposed even on the most narrow of apertures. This is a guy who is into his photography and has a particularily expensive Nikon DSLR. Obviously what he needed was an ND filter to stop some light. How did I know this?.... read it in a book So "Is learning all this stuff going to make you a better photographer or enjoy the process any more than you do now?" Well in this chaps case it certainly would have.

Learning techniques to control light is, I'd argue, worth ten times more than learning about the lens design and which lens has different groupings of how many elements, and is it a 9 or 7 blade aperture. It'll have a greater impact on your output.
In a way, if you're learning to drive, learn to drive. Don't worry about how the engines built.
Either way, I hope you enjoy the studying.

Yeah, but once you are ready to buy a car, it helps if you understand BHP, CC, MPG as well as handling etc.

Ahh, car analogies...
There was something on Top Gear a few weeks ago - those who show no interest in their cars and end up buying something crap probably have very little interest in driving too and as a result are likely to be a liability. I know where Mr Trigen is coming from - knowledge will help you make an informed choice about the kit you buy - how lenses work and which characteristics to go for, such as going for the smallest aperture you can afford for a given focal length etc. Trouble is, theory is all well and good if what looks like a good lens on paper turns out to be dreadful - one that extends by itself if you point at the floor, one that has a lot of chromatic aberration or one that just feels like it came out of a box of cornflakes. Same goes for the camera bodies - some bodies sound great on paper but end up having metering problems, reliability problems, are uncomfortable or like the lenses, feel like something that dropped out of a cornflakes box.

Instead of reading up on the theory, I would personally think first about the shot I want to take and then think about what kit I would need for that shot - then find out what is available that best suits your needs and why - much of the theory applies across the board, but only the characteristics of the real life kit matters.

As for books to try, a friend of mine is doing a photography degree - I'll see if I can get his reading list from him.

The other option is to take your camera and take the same shot with different camera settings. This gives you a chance to review each setting. The EXIF data will tell you focal length, shutter speed, aperture etc.. You will then start to learn what settings work for you, and you can go from there.

I take your comments as fair and I understand where you are coming from. At the end of the day, I learnt about aperture, depth of field, focal length, exposure and lots of other things from a book. All I want is a reference book for the digital age instead of the one that I have. I looked at the updated version of the one I already own in WH Smith the other day although I wouldn't have bought it and it still looks like only a passing nod has been given to the digital age- it still covers daylight and tungsten balanced film!

Understanding the technical nature of an activity doesn't harm anything unless you get too clinical instead of creative, I suppose but even after all my years of SLR experience, (almost 12 years now) I still feel like I haven't got a clue at times. I already recognise that I have to throw time and/or money at this activity. Time, I can find, money is not something I can throw about in such large quantities and I need to understand what I need to head in the direction that I wish to go.

For example, I just bought my macro lens. Awesome performance and excellent potential, but it's clear that for all but the brightest lit and/or static subjects a flash is going to be useful. Canon ring/macro flashes are disgustingly expensive, but I've got my eye on a cheaper one. I might end up disappointed with it. Understanding what expensive flashes are all about would help me to know whether the extra price is worth paying.

Short snippets of information I am happy to get from the Internet, but I hate trying to digest vast amounts of information on screen. I'll make a good start with my new books, including the Magic Lantern book, Paul and see where I am at.

Try a reflector. You can get small ones which collapse down and it into your bag. They are very good, and will throw light around. Try a tripod and long exposures.