Look beneath the surface of many great business successes, and you're likely to find a trail of failures that preceded them. Describing the painstaking trial-and-error process that led eventually to the creation of the incandescent light bulb--and General Electric--prolific inventor Thomas Edison said "I have not failed. I have merely found 10,000 ways that won't work." Many people would have given up, but Edison had the heart of The Experimenter. Henry Petroski, in his classic book To Engineer is Human, says that in his field, failure is almost a prerequisite for success, because only by reaching a point of failure can you define the limits of possibility. I am not sure I would interpret that idea literally for business vetntures, but I do know that lots of stellar successes are built directly on a series of small failures. British entrepreneur James Dyson reports that he built 5,127 prototypes of his cyclonic vacuum before getting to one that was commercially successful. That dedication to the Experimenter role is truly extraordinary, but so was the reward the now-billionaire Dyson eventually received. At IDEO where I work, we try to maintain a sense of "joyful failure" about quick early prototypes, knowing that learning from those first rough versions will point us in the direction of future successes.