On the advice of Morris Proctor at a recent Camp Logos I am now in the process of tagging all the books in my library. For the most part I have followed his suggestions regarding subject tags and author tags. I have also seen the wiki on collections that also helps with tagging. However, I am curious if there are any tags that other users have found especially helpful for doing bible study, sermon preparation, etc. Author tags are pretty straightforward so I suppose I am primarily looking for subject matter tags. Any thoughts?