BAND-AID -- Earle Dickson was a cotton buyer for the Johnson gauze bandage company. Marriage made him an inventor: His bride kept hurting herself in minor ways, and so he devised a small, ready-made sterile bandage strip. Since 1921, Johnson & Johnson estimates 100 billion Band-Aids have covered skinned knees and other cuts and scrapes.

PHOTOCOPIER -- Think about what once was involved in making a copy. Monks toiling over medieval manuscripts. Smudgy carbon paper. Enter Chester F. Carlson. In a neighborhood in Queens, N.Y., he used powdered ink and an electrical charge to create a photocopy. ``10-28-38 Astoria,'' the reproduced page said, identifying the date and place.

BALLPOINT PEN -- World War II could not stop Laszlo Biro's invention; indeed it hastened production. Biro was working on a ballpoint when he fled his native Hungary, and he patented it in 1943 in Argentina. Some 30,000 pens were soon manufactured in England so RAF navigators could write in unpressurized cockpits where fountain pens failed.

FRISBEE -- Working independently at mid-century, Bill Robes in New Hampshire and Frederick Morrison in Los Angeles created the ``Space Saucer'' and the ``Pluto Platter,'' respectively. Whether the name Frisbee derives from a pie company whose tins Yale students tossed is a matter of debate. (Honorable mention toys: Slinky, 1946; skateboard, 1958.)

STICKY NOTES -- First came Spencer Silver's 1973 invention of an indifferently sticky stuff. But what to do with it? His 3M colleague, Arthur Fry, had the application: He first used paper gummed with the stuff to mark songs in his choir book. Today, these scraps of square pastel are our universal reminders.

(Sources: ``Panati's Extraordinary Origins of Everyday Things''; ``David Wallechinsky's Twentieth Century''; Utne Reader, The Economist)

Copyright 1999, Associated Press