Second Great and Bountiful Human Empire

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The Second Great and Bountiful Human Empire was a political entity with influence in three galaxies. By the 42nd century, it had spread from an overcrowded Earth throughout that galaxy of Mutter's Spiral and two others. Earth was a crowded planet. The currency of the Empire was the credit. (DW: Planet of the Ood)

Most likely this was also the empire referred to which send out the Walker Expedition. If so, Zachary Cross Flane's remarks about saving the Empire and the Walker Expedition's aim of finding new energy sources would have significance.
Unless it would refer to the Earth Empire, we know nothing about the First Great and Bountiful Human Empire or about the Third.

See also