This document provides information about business letters, including their definition, purpose, parts, styles, and tips for writing them effectively. Business letters are a formal means of communication between companies used to inform or persuade. They generally have five main parts: the date, inside address, salutation, body, and closing. The document also discusses personal business letters and persuasive letters, outlining the AIDA formula. It provides checklists for writing concisely and effectively as well as dos and don'ts for business letter composition. Proofreading is emphasized as important before sending any letter.