Everywhere you look today -- from buildings and landscapes, to commercial products and public services, to Web sites and print products -- design has taken on new meaning. Design isn't just about decoration; it's a critical component of how we communicate, collaborate, and compete. But behind the "look and feel" of any good design are a host of carefully conceived principles: fundamental propositions that define the essence of the design. The trick for all businesspeople today is to learn those underlying rules -- to think like designers. With that in mind, Fast Company asked 15 top designers -- creators of buildings, furniture, products, Web sites, costumes, and labels -- to deconstruct something that exemplifies great design to them. More important, we asked them to tell us what we can learn about the art of design. Read their thoughts, and then take out a sketchbook and start designing your own world.

Terence Conran

Founder and chairman
Conran Holdings Ltd.
London, England

Good design is probably 98% common sense. Above all, an object must function well and efficiently -- and getting that part right requires a good deal of time and attention.

The Dyson vacuum cleaner is a good example of that commonsense approach to design. Why? It's bagless. People always moan about vacuum-cleaner bags. Every so often, you have to remember to buy more. The bags are often hard to find, and no two models of vacuum cleaner seem to use the same bag. And they're difficult to remove and to replace. So the attraction of a bagless cleaner is obvious. Debris is collected in a clear chamber, so that you can see how much you have picked up. You then simply remove the chamber, empty it, and put it back.

The Dyson's "livery" colors of gray and yellow -- design is 2% aesthetics -- recall the colors of medieval craftsmen's guilds, giving the product an aura of reliability. The colors also make Dyson vacuums universally identifiable, like London's red double-decker buses or New York's bright-yellow taxis.

I particularly like Dyson's DC02 and DC05 cylinder-model vacuums, which look like robots or giant bugs. They make you smile -- which is an unusual response to a household appliance. But again, the aesthetics are almost accidental. The slightly squat appearance is an example of form following function: The Dyson can sit on a stair or negotiate a corner much more easily than most other cylinder vacuums can.

Sir Terence Conran founded the Habitat chain of stores and is chairman of Conran & Partners, his London architecture and design firm. He is one of the world's leading designers, furniture makers, restaurateurs, and retailers. The first Dyson vacuum cleaners were sold in Japan in 1991 for $2,000 each.

Adrianne Philips

Costume designer
Los Angeles, California

The boundaries between design and art constantly intersect. But design, for me, is never frivolous. And one of the essential elements that differentiates design from art is function. Take, for instance, the Citroen car. I'm not a real car person, but I remember being completely entranced when I saw this car for the first time. It was the perfect mixture of practicality, beauty, mystique, and sophistication. It had a European sensibility that to me, as a young American, was exotic. The car had beautiful lines and looked sleek and compact. What's more, the inside was roomy enough to seat four people comfortably.