MOMA had a display about the 50th anniversary of Helvetica last year.
Douglas Hofstadter has written quite a bit about fonts and typeface. His slant is towards how it relates to machine intelligence and if it's theoretically possible to create determinate models to distinguish between letters programatically, but he also just generally likes the topic of fonts. The book
Metamagical Themas: Questing For The Essence Of Mind And Pattern is a collection of columns he wrote, so you can skip to just the ones about type if you don't want to wade through all his other stuff (though everything else is fascinating as well, even if he is a little too obsessed with Rubiks).