For twenty-five years the colossal battle between Megatron and Optimus Prime has captivated Transformers fans around the world. Yet the full story of the conflict between the two most famous Transformers—everything that happened before Optimus and Megatron arrived on planet Earth—has always been a mystery . . . until now. Here, for the first time told in its entirety, is the thrilling saga of Optimus and Megatron before they were enemies, before they even knew each other.
'For the first time'? 'Always been a mystery'?

Over the 25 years of 'battle between Megatron and Optimus' we've had quite a few 'before they knew each other' and pre-Earth stories.
For them to market this as being the first ever story that tells about the pre-Earth history of the Transformers, entire or not (nothing is ever entire), it is misleading, false advertising.

They should have said that it was just the pre-Earth history of the current series (WfC), as it seems that they are claiming that it will explain the pre-history of the entire 25 year Universe of Transformers (which isn't all in the one continuity anyway).