Ross Guberman. I highly recommend his seminar for all writers. Take it if you get a chance. He has written a book, Point Made, that I intend to read.
He mentioned a book by a graphic designer/lawyer, Typography for Lawyers, by Matthew Butterick. He didn't really recommend it, but I pass it on because I know at least one of my blog brothers is interested in fonts. It discusses fonts at length; it also covers document layout and other graphic design topics.