Marketing plays a really large role on the realm of inventions and discoveries. The person who is attributed with the invention is not necessarily the one who first developed the concept but rather the one who market himself better. The Shuzak blog has an interesting article listing 9 inventions that Thomas Edison did not make, contrary to the popular belief.
The first one is the light bulb: “Ask any child who invented the light bulb, and the answer is likely to be “Thomas Edison”. Contrary to what schools have taught for years, the American icon, Thomas Edison, neither invented the light bulb, nor held the first patent to the modern design of the light bulb. In reality, light bulbs used as electric lights existed 50 years prior to Thomas Edison’s 1879 patent date. In fact, Edison lost all patent rights to the light bulb both in Britain and the United States.”
The other eight inventions are:
2. The Electric Chair
3. The Movie Camera
4. The Power Generator
5. X-Ray Photographs (fluoroscope)
6. The Storage Battery
7. The Record Player
8. Wax Paper
9. The Telegraph
You can the long description for each invention here.