Evolution Technological Degrees (simply named TDs) here presented, have to be used as basis for different Backgrounds, therefore they do not refer to human society, but to a generic race under evolution.
Doom may decide to use different technological eras or to modify some parameter (e.g. mixing together components from more than one TD), according to different historical or social situations that took place in its Background. This way, you can even play Backgrounds for human race, in which past historical events took place in different way from ours (Historic-Fiction Background or Alternate Histories).
Each TD below is described providing its name, a short description and a list of standard reference parameters.