William Gibson, talking about why he uses all-caps book titles, gives a short history lesson regarding the rendering of book titles, back in the age of the mimeograph:
Much of my earliest typewriting experience had to do with mimeography, a pre-thermocopy form of reproduction once fairly universal in the world’s offices. You typed, once, on a waxed paper ‘stencil’, clipped this over a silkscreen device with a moving pad or drum of ink behind it, and your mimeograph ran off (or silkscreened, really) as many copies of your document as you required. Owing to the physical peculiarities of the medium, though, it was unwise to underline too frequently on a mimeograph stencil: the single unbroken line was particularly prone to tear, producing leaks and smudging.
People who liked books, and frequently wrote letters, on typewriters, to other people who liked books, tended, free from the constraints of an academic stylesheet, to render titles in all-caps. People who wrote about books for publication in amateur journals (mimeo was an authentic medium of the American samisdat) rendered titles in all-caps in order to avoid stencil-tears. At various times, I was both.
It’s such a pleasure having this kind of stuff to read every day!