I highly recommend The Elements of Typographic Style if you actually want to "understand" type and how it works (and why Helvetica should be kicking Arial's ass). The world of typefaces (and not fonts) is much richer than the free faces that came with your computer. I'm constantly amazed at "designers" today that don't understand basic typography. I was lucky enough to
work with learn from Robert Wakeman, the O&M Type Director back in the day. Robert would hand kern IBM Bodoni headlines. His knowledge of typography was Herculean.