This document discusses communication in professional structures. It defines four types of professional structures: entrepreneurial, pyramid, matrix, and independent. In an entrepreneurial structure, decisions are made centrally. A pyramid structure involves shared decision-making and specialization. A matrix structure involves project teams with individuals having specific skills and responsibilities. An independent structure provides support systems for professionals but little organizational control. The document provides examples of each structure type and exercises to match organization examples to structures. It also discusses vertical communication flowing up and down hierarchies and lateral communication between equal levels or departments.