I have never used Lightroom, but want to begin using it. I have many GB of images in a number of folders on backup drives, as well as newer images on my computer. I typically backup new images to an external drive, then transfer processed images to the backup drive. Folder names on my computer match folder names on the backup drives.
What is the best workflow to process all of the images that I have in Lightroom? Should I bring folders from the backup drives back onto my computer, run them through the Lightroom library, then transfer them back onto the external hard drives?
No. You can just import them from the external drives. Just be sure to import them into the data base only. Don't move them.
Also if you begin using Lightroom then it will be best to move any future images from within Lightroom. That way the database will be able to "find" all your images without you having to go look for them. You should also allocate fixed drive letters/names to your external drives.
if you're just going to experiment w/ LR, you can leave everything where it is and 'import' by reference (ie. w/o copying). It's the fastest and simplest way.
if you decide you're going buy & use it, you'll want to rethink you're overall storage strategy before you endlessly start moving things around.
once you 'import' (even w/o copying), if you decide to start moving files around, do it from INSIDE LR or else LR will essentially lose track of them and then you have to tell LR where you moved them to, etc which can be a PITA.
Thanks for your advice. On recommendation, I have downloaded some good videos on LR from Luminous Landscape. I find them quite helpful, and go along with your recommendations.