We're about to step back into a time before PDA's and laptops, to an age when the word 'computer' meant something entirely different. No, we're not talking about primitive Commodore desktops. Or even those old vacuum-tubed Univacs that would fill up whole rooms. We're going back to a period nearly everyone seems to have forgotten. A time when computers were - human. David Grier teaches technology policy at George Washington University. He's now written the first in-depth account of a career that no longer exists. Grier describes 'human computers' as people who did the blue collar work of the mind.