Absorption was the name for the method by which new individuals were added to the Body of Landru. The members, or parts, of the body existed in quiet bliss. Within the body, there was no crime, no disease, no war, none of the "ancient evils" – only joy and contentment. There was also no advancement, no spark, no "soul", so to speak. The Body, the civilization of Beta III, was completely stagnant. Social conditions had not changed since Landru rose to power, 6,000 years earlier.
Two methods of absorption were noted. Lawgivers could absorb individuals using a function of their staffs. The second method involved a futuristic room, the absorption chamber. In this room, one of the very few technologically advanced rooms on Beta III at this time, an individual was secured to the wall, and an operator (often but not always, a lawgiver) processed him using a sophisticated control panel.
Both methods appeared to produce the same result; the subject's individuality was subsumed into "the unity of good". The members of the Body had some limited degree of free will; Landru imposed upon them a series of general guidelines called the Directives; these governed their attitude and conduct. Those in the Body did not forget their lives before absorption, but these were important to them only to the degree that they conformed to Landru's directives. Landru could communicate with the members of the body, and could, if necessary, focus its awareness through specific members. Although Landru did not exert absolute control over every member of the body at all times, it could control any member of the body quickly and at need. When not under direct control, members were governed by the directives. Despite the lack of constant oversight, some form of transmission or control connected Landru and all the members of the Body at all times. This required at least minimal oversight from Landru; as it focused its computing power on problem solving, its influence over the Body began to wane. And when it ceased to function, the effects of absorption ended immediately.
The lawgivers, Landru's foot soldiers, were an exception. These individuals were under deep control at all times, and were the only individuals that could initiate conversations with Landru, a process called communing.
Certain residents of Beta III were immune to absorption. Many of these individuals organized themselves into a kind of underground, to resist the will of Landru. The USS Enterprise landing party encountered three such individuals: Reger, Tamar, and Marplon. There is some evidence that Landru moved quickly to destroy such individuals when it located them; lawgivers summarily executed Tamar when they learned he was not of the Body. (TOS: "The Return of the Archons")