There's a difference between fashionably late and inexcusably late. And those few minutes can be critical when it comes to arriving at after-hours business gatherings and whether or not you leave a good impression with colleagues, managers and others who wield influence on your career.

Husband and wife attorneys David and Donna Gerson, of Mt. Lebanon, tackle the intricacies of late arrivals and other topics of manners and protocol in a new guide, "The Modern Rules of Business Etiquette." Published by the American Bar Association, the concise, 89-page paperback is aimed mainly at lawyers and draws on the authors' own professional experience working in law firms and the legal community.

But tips on how to behave in an interview (get the directions right and don't bill for the minibar at the hotel where they put you up) or how to work with senior staff members (be eager, timely and responsive) easily can transfer to other careers.

"It truly has universal appeal," said Donna Gerson. "Having a sensitivity to etiquette will serve you well in any profession."

Take the lateness issue. For group gatherings or large parties that include a cocktail hour, fashionably late means arriving up to 15 minutes after the start time. Show up any later and you're inexcusably late. You should be very time-conscious for sit-down dinners. According to this guide, it's proper to ask the host or hostess for a precise start time. "You don't want to walk into a room with everyone seated and enjoying their appetizers," it cautions.

Ms. Gerson, formerly the director of the career services office at the University of Pittsburgh School of Law, writes articles for legal publications and speaks to law firms and law students about career issues. Mr. Gerson is a partner in Morgan Lewis & Bockius' Pittsburgh office. They met as undergraduates at the University of Pennsylvania then earned law degrees: hers from Temple University and his from Harvard Law School.

When the ABA proposed she write a book on etiquette, Ms. Gerson recalled, "I impulsively said, 'It would be so much fun to do this with my husband.'"

Mr. Gerson "initially responded with horror," said his wife. "But then with acceptance that this was a good opportunity."

He contributed most of the advice for how to behave in typical office situations, such as working with senior and junior staff members, dealing with clients and how to handle opposing counsel. There's even a polite and proper way to introduce all the parties on a conference call.

Ms. Gerson focused on the chapters about interviews, social events and job changes.

For instance, not only is it bad manners to speak negatively about former employers and employees, but someone at your former workplace also could initiate legal action against you over such remarks.

"You never want to denigrate a former employer," said Ms. Gerson. "People are very connected. You don't know who's married to whom or connected to whom, and it will undoubtedly get back to that person."

Is there still a place for etiquette in an age where people go for days or weeks without meeting but stay in touch via cell phones and e-mails?

"Personally, I think so," said Ms. Gerson. "There's a richness of connection that is missed when you are just conference calling or e-mailing .... We're developing a point-and-click mentality from purchasing goods to personal connections."

Practicing etiquette also can benefit your business strategy, the Gersons conclude. When you are polite and composed, those you do business with will find it tougher to raise their voices or exhibit outrage when they disagree. Whether they become complacent, frustrated or disoriented in the face of etiquette, there will be "opportunities to turn a situation to the benefit of the more well-behaved party."