The research trees unlock additional units and upgrades. Progression up the zerg tree is through accumulating zerg research points in missions, with protoss research points being applied to the protoss tree. Collecting points and advancing up the trees are a type of quest. A visual indication of how far research has progressed is available on the left side of the library. It is present in the form of two tubes, one each for protoss and zerg research. Clicking on either of these accesses Stetmann's research log.