Decades after the first guides to workplace behavior appeared, says Barbara Pachter, people remain unsure how to properly shake hands and host a business dinner—and constantly changing technology presents a series of fresh challenges. In The Essentials of Business Etiquette: How to Greet, Eat, and Tweet Your Way to Success, Pachter takes on a wide range of up-to-date proper business behavior, and this Q&A with her addresses some key questions. Pachter notes that even successful veteran executives are hardly exempt from etiquette advice. "They often need more than they think," she says.