This document discusses group boundaries and dynamics. It begins by explaining the theory of under-bounded and over-bounded systems, where over-bounded systems have less permeability than optimal and under-bounded systems have more. It then examines different types of boundaries including authority, identity, and those around task, time and authority. Key variables that differentiate under-bounded and over-bounded systems are identified such as goals, communication patterns, and affect distribution. The authority boundary and its sources from above, below and within are explored.