Exactly 5,126 attempts to make the first bagless vacuum cleaner were failures-some catastrophic disappointments, some minor defects. It took 15 years. Prototype 5,127 was the success ... Failure is painful, but it spurs on improvement like nothing else.

I've fought court battles over my inventions before.

Designing aircraft and racing cars is an extremely exciting thing.

Engineers are behind the cars we drive, the pills we pop and the way we power our homes.

If you really want to improve technology, if you want things to work better and be better, you've got to protect the person who spends a lot of effort, money, and time developing that new technology.

What I've learned from running is that the time to push hard is when you're hurting like crazy and you want to give up. Success is often just around the corner.

Successes teach you nothing. Failures teach you everything. Making mistakes is the most important thing you can do.