The term holacracy is derived from the term holarchy, coined by Arthur Koestler in his 1967 book The Ghost in the Machine. A holarchy is composed of holons (Greek: ὅλον, holon neuter form of ὅλος, holos "whole") or units that are autonomous and self-reliant, but also dependent on the greater whole of which they are part.[5] Thus a holarchy is a hierarchy of self-regulating holons that function both as autonomous wholes and as dependent parts.[5]