You can accomplish a great deal through the combination of Photoshop actions and the built-in features on Bridge's Tools menu, but actions do have some limitations. You can build amazingly complex actions, but the editing environment is a nightmare once you get beyond a dozen or so action steps, and debugging can be a serious chore.
If I were to attempt to cover scripting in any depth at all, this book would instantly double in length, so I'll content myself with making you aware of the resources that Adobe supplies. Scripting is most certainly not for everyone, but if you've completely digested, implemented, and exhausted all the techniques in this book, and you want more automation, it's the next world to conquer.
If scripting is something you place in the same category as root canal therapy without the benefit of anaesthesia, you're far from alone. But Bridge's scriptability presents huge opportunities for those who actually enjoy such things, and I fully expect to see a plethora of scripted solutions, some free, some commercial, that will extend Bridge's functionality in all sorts of useful ways.
Right now, Bridge is where Photoshop was before the days of third-party plug-ins (yes, I go back that far), but this is not a situation that will last long. So keep an eye out for useful third-party solutions that plug some of the gaps in Bridgea good place to start is the new Bridge Forum on Adobe's User-to-User Forum. Who knows, the market for Bridge scripts may actually turn out to be bigger than the Photoshop plug-in market.
The more you automate your workflow, the more time you'll have to actually practice photography, which presumably is what drew you to this book in the first place, and is certainly what motivated me to write it.