its set in the classic traveller setting, same as CT and MgT 1e.
the rulebook is flavour light, but that's so you cen build your own setting if you want, which has always been a big part of the traveller gaming community.
I'd suggest getting the MgT 1e Spinward Marches sector book, which is 100% compatible with 2e (since it doesn't contain any rules, just setting info)