The fourth book describes the adventures of the renaissance genius Leonardo Da Brewster who succeeds in raising the treasure of the lost knowledge.
In the course of an exceptionally long life caused by a genetic experiment, he is leading the humans back into modern times and finally he restores the democratic system while risking cunning confrontations with the totalitarian government.
Close to the end of his existence he constructs a synthetic body, orders to have his brain transplanted into it and achieves immortality as a cyborg.
Please bear in mind that all novels lack an English translation. They are only available in German.