The document discusses four theories of selling: 1. AIDAS theory focuses on securing attention, gaining interest, inducing desire, inducing action, and building satisfaction. 2. "Right set of circumstances" theory emphasizes that the salesperson must control the selling situation by handling external factors like themselves and remarks, as well as internal factors about the prospect. 3. "Buying formula" theory focuses on the buyer's needs and problems, potential solutions, purchase decisions, and satisfaction or dissatisfaction after purchase. 4. "Behavioral equation" theory uses a stimuli-response model to analyze drives, cues, responses, and reinforcement in the buyer's decision process.