PowerBook Duo

The PowerBook Duo, launched in 1992, chased a genuinely different idea: an ultra-thin, ultra-light laptop that sacrificed built-in ports and a floppy drive to get there, meant to dock into a full desktop setup (the Duo Dock) when you got back to your desk.

Models like the Duo 210, 230, and the color-screened 270c and 280c pushed that subnotebook concept about as far as early-'90s hardware allowed. It's an idea Apple would circle back to, in spirit if not in specifics, decades later with the MacBook Air.