-Oldstyle: Diagonal stress, Serif (lowercase serif slanted), Moderate thick/thin, based on handlettering of scribes, (curved serif)
-Modern: straight Serifs (horizontal and thing)severe thick/thin transition, no slant, stress is perfectly vertical, hard to read when its small (not even feet)
-Slab Serif: Little or no thick/thin transition, Clarendon/Egyptian, Vertical stress, Square serifs (little points stick out but there even)
-Sans Serif: no serifs, no thick/thin transition, monoweight, easier to read from a distance and on screen EVEN
-Script: use sparingly, never all caps (cursive)
-Decorative: You'll know it when you see it...