One of the challenges of presenting history is its inability to be captured by a single interpretation. The goal, therefore, must be to find neutral ground and present opposing points of view where appropriate. Truth must not be a victim of this process. For example, it would be wrong if the different versions of Encarta provided dramatically different accounts of Waterloo. As it happens, the text of the accounts is almost identical in the US, British, German and French editions of the encyclopaedia.
Differences are subtle, but they matter.
For the record, Swan did invent the light before Edison, although their efforts were independent. But Edison turned it into a commercial success. And Bell invented the electric telephone, after Meucci conceived of a simpler mechanical device that allowed remote conversations over relatively short distances. At least, that's reality as I understand it.