This document discusses key principles of interior design including balance, rhythm, space, emphasis, and unity. It defines each principle and provides examples to illustrate how they are applied. Balance can be symmetrical, asymmetrical, or radial and is used to create visual equilibrium. Rhythm introduces order and interest through repetition or alternation of design elements. Space refers to the three-dimensional area defined by length, width, and height. Emphasis is used to create focal points. Unity is achieved when all design elements work cohesively to create a unified whole.