Technologies
The various technologies used to enable travel and civilization on the galactic scale are immense in their complexity yet still follow the same basic lines as technologies readers may be familiar with. There are computing needs, travel needs, communication needs, and climate control needs, all powered by, essentially, electricity. The listed sections will cover those technologies, from the containment systems used to house and harvest energy from singularities to the tin foil used in spacecraft to protect them from radiation.
It's not tin, it's actually a carbon-lead molecular lattice. But it looks just like really thin tin foil.