Some good books I have about the technical side of theatre (outside stage management) are:
Theatrical Design and Production by J. Michael Gillette:
This is the textbook I used in college for my intro level classes in lighting and sound. I still use it as a reference when I have to tackle a technical job or problem. It has information about all aspects of technical theatre and I have not found the need to purchase any other books for basic things. I always go here first, and then google more specialized questions I may have. It also goes into makeup, costuming, scenic elements and the design process. I wouldn't suggest sitting down and reading it cover to cover (I haven't seen the need for that) but rather as a good reference book. I have the 5th edition from 2005, but it looks like they released a 7th edition last year. It is on Amazon.
Scene Painting Projects for Theatre by Stephen Sherwin:
I got this book just recently when I took a job at a high school as the TD and needed to supervise painting. It goes into depth and step by step for all sorts of theatrical painting techniques. It has really great pictures of what each step should look like. It was developed by a scenic painting teacher after he realized that a book like this doesn't exist. It is a great resource if you need this kind of specific information. I had to special order this one from Barnes and Nobel.
I agree that it is great to have a foundation in theory before you learn in a hands on way, so props to you for taking the first step. Your education is always what you make of it. I think it is really great too to have reference materials because sometimes you will have long stretches of time where you don't have to worry about anything technical, and then you get a job where you are expected to mix sound or change lamps and it is nice to be able to read up on how to do it and give yourself a refresher. You can always google these things, but there is something to be said for a good book (that is another discussion entirely!).
Hope this helps!