Sector General was founded to promote inter-species harmony, and therefore all medical staff must be prepared to treat beings with very different physiologies and behavior patterns, and sometimes with environmental requirements that would be lethal to staff without suitable protection. The hospital uses a four-letter system to assign patients to wards that provide suitable environments, a classification technique used earlier by E. E. "Doc" Smith's "Children of the Lens". White's "Star Healer" introduces the classification "FOKT", which is regarded as an in-joke on the name of the Glasgow science fiction club Friends of Kilgore Trout.