Tomorrow Becomes Yesterday is a book in Deus Ex: Invisible War. It is an excerpt from a longer book documenting the history of VersaLife. The title is a reference to VersaLife's slogan, "We make tomorrow look like yesterday".
Chapter XII: The Grays
The mysterious Gray continues to elude researchers. They are suspected to be more intelligent and less belligerent than other transgenics. Some theorize that the Grays were being evolved as shock troopers for extreme conditions.