The document discusses four types of business messages: positive, negative, neutral, and persuasive. Positive messages convey good feelings through letters like appreciation, thanks, and sympathy. Negative messages convey disappointment through letters like disapproval, refusal, and cancellation. Neutral messages convey information and require action through routine letters, reports, and reminders. Persuasive messages aim to gain agreement by demanding action through memos, invitations, and brochures. Examples of each type of message are also provided.