Back in time to 100 BC, what knowledge would you impart to the people?
Travis: I would tell them the benefits of standardization and assemblage.  Making things to specification is a little appreciated, but very useful, concept.E.g., a component of America's success in many wars (although I've read the disparity between her forces and the enemies were greatest during the Revolutionary War) was the fact that the gunsmiths made parts to spec.  So I could buy my gun in NY and have it repaired with off the shelf parts down in Virginia.For all the printing press folks, I think a big part of the success of the Gutenberg press was the fact that it was one design, could be build and distributed, and could be fixed from standard parts.  Don't ever underestimate the influence of maintenance!