Contrary to the popular belief, Thomas Edison had basically nothing in common with invention of the light-bulb and very little with its development. His actual contribution would be more of a popularization of that invention and organizing mass production than anything. It should be remembered, however, that pinpointing the 'invention' of the light-bulb is quite difficult, as this particular device has been thoroughly re-worked and developed for over a century (or almost two centuries if we include the earliest successful experiments) before achieving its modern shape.

The first recorded demonstration of the electroincandescence (the production of visible light through the application of electric current) is attributed to Ebenezer Kinnersley, an England-born scholar of College of Philadelphia who have performed the demonstration in 1761, while he was working on the usage of electricity to generate heat. Humphry Davy independently have demonstrated in a similar way 1802 that the metal strip of platinum could be used as a light source when connected to the source of a direct current. The results of both experiments were far from practical given the low luminescence and high cost of equipment used, but it laid the groundwork for further developments.

The term 'light-bulb' (or rather Incandescent Light Bulb) is attributed to James Lindsay, another Scottish inventor who created an evidently practical electric light in 1835, building a light source comparable of that of a candle. This was his side-project however, and was not developed further. In 1840, Warren de la Rue created a device that is in many ways an earliest specimen similar to modern light-bulb - a thin metal strip made of a metal with high melting point encased in a glass bulb with the air evacuated (a near-vacuum light bulb). Two years earlier, a Belgian inventor Marcellin Jobard also created similar device but using a carbon filament instead of a metal one. The very first pattern for a device we might call a 'light-bulb' has been granted to Frederick de Moyens who experimented with both metal and carbon filaments, but selected the former as a basis for the patent.

Meanwhile in Russia, Alexandr Lodygin independently develops a similar device in 1872 and obtains the patent for it two years later. In opposition to his Western colleagues, he decides not to evacuate the bulb to create near-vacuum, but rather decides to fill it with an inert gas, a process that is used in modern bulb, but quite possibly due to technological constraints, he used nitrogen rather than argon or xenon that are used nowadays. Also in 1874 two Canadian inventors, Matthew Evans and Henry Woodward developed a similar carbon-filament light-bulb filled with nitrogen, but after marketing failure they decided to sell their patent to Thomas Edison. In England, Joseph Swan has been working on the electric light-bulb since 1840's, focusing on the vacuum lamps with carbon filaments. Being as much an inventor as a entrepreneur, Swan actively sought the popularization of the electric lighting in England and formed a turbulent partnership with Edison in 1880s.

Thomas Alva Edison enters the scene by focusing on the development of the electric light only in 1878, so he cannot be considered an inventor of a light-bulb by any means. The actual bulb he has been working on was actually patented by Moses Gerris Farmer (renowned for being the creator of the forst electric train in USA) in 1859 and later bought by Edison. As said before, Edison did not contribute much to the development of the light-bulb as such (he focused on carbon filaments that were ultimately found to be a dead end) but he did a lot to popularize the invention, developing methods of mass-production of the filaments and bulbs (including Arturo Malignani's patent for the more efficient evacuation method acquired in 1895) as well as establishing the Electro-Dynamic Light Company (later United States Electric Lighting Company) in 1878 to capitalize on the growing popularity of the new illumination devices. Additionally, he entered a partnership with Swan, forming Edison and Swan United Electric Company in England.

The development of the light-bulb took and interesting turn in 1897, when German physicist Walther Nernst developed a ceramic-carbide based lamp that has not required a vacuum or an inert gas environment to operate and were much more efficient than all carbon-based light-bulb developed to that date. They quickly gained popularity, but were ultimately outperformed (save for few specialized uses, such as the generation of near-infrared radiation) by the device that we can call the first modern light-bulb. This has been constructed and patented in Austro-Hungary by Sandor Just and Franjo Hanaman in 1904. Their light-bulb was a glass container filled with argon and using a tungsten (wolfram) filament, much like the bulbs we use nowadays (on a side note, their company Tungsram, named after the material the decided to use, exists to this day, operating until 1992 as an independent company and after that as General Electric subsidiary). The final touches has been finally made by an American Bernie Lee Benbow of GE Cleveland who received a patent for the 'coiled coil filament' (a coiled wire additionally wound in a larger coil itself) in 1917 and Japanese Junichi Miura who created the first double-coil light-bulb in 1921 while working for Hakunetsusha company, where he followed by obtaining a patent for a machine allowing the large-scale production of the double coil filaments in 1936.

So, to sum this up, the first concept of the light-bulb with accompanying proof appeared in early 1760s courtesy of Ebenezer Kinnersley. The first practical application of the electricity as a light source is the work of James Lindsay in 1835, the more or less practical light-bulbs using metal or carbon filament were being made by various people between 1830s and 1900s, until they gained more or less modern shape in 1904 thanks to Just and Hanaman with some minor tweaks being introduced in the following decades.