Technical aspects aside, K&R has what some modern books seem to lack: a really clear and comprehensive layout. I've picked up a few modern books and immediately noticed how they make use of thinner (thinner != smaller) fonts that make then hard to distinguish. At first I thought it was my fault for being old and wearing glasses, but as soon as I opened back some other old books like the K&R, the Niklaus Wirth (Algorithms+Data Structures = programs) and a couple other ones, I could read again without effort at the same distance wearing the same pair of glasses. Why do they use fonts that thin today?