How much detail does the rpg book go into on the backround of wissenschaft?
Sadly not much, at least not as much as we would wish. Keep in mind that a little more than half a part of the RPG book are the rules for the game and the rest is dedicated to fluff, but it happens the background for Anima universe is huge. A lot of things to tell and know! To tell the truth, if you plan on buying the book just for Wiss fluff then you'd better wait for the Anima Tactics Saga II Rulebook

You can find more fluff in the Gaia book, thanks to the briefing about the Lucrecio region and its lands (in Gaia, every region in the old continentis reviewed town per town, city per city; the new continent will be treated in the future Gaia II ) but once again, despite having even two pages for Lucanor, it lets you wishing for more detail.
I do really hope the upcoming in the future book "Lost Logias" will reveal more background about their technology and the organization.