I also found use of the word "humanists" confusing.  The types of people listed preceding "humanists" are defined by what they *do* (i.e. study, teach, do medical research) which makes sense in the context of talking about the commonplace book as one of their tools.  "Humanists" defines people of a certain ethical ideologywhat does that have to do with the function of a commonplace book?  Is the use of a commonplace book particularly defined by one's world perspective?  To me this would be akin to writing "many blogs are maintained by writers, professors, lawyers, editorialists, and Republicans/Democrats" in an article about blogs.  True though it may be, it confuses the reader into thinking that the subject being written about is somehow ideologically specific when it is not.