The document discusses the different parts and styles of layout for business letters. It describes the standard parts of a business letter including the date, inside address, salutation, body, complimentary close and signature. It then explains 4 common styles of layout - full block form, semi-block form, modified block form, and hanging indentation form. Each style is defined in terms of how address, date, paragraphs and other parts are arranged on the page. The full block form saves time by having no indentations but looks unbalanced, while the hanging indentation form is unusual but distracting. The modified block form and semi-block form provide more attractive appearances while still being efficient.