(FORTUNE Magazine) – DEAR ANNIE: I just took on an important new job for my employer, and I'd like a salary increase. My last pay raise was four years ago (before the new responsibilities), to $42,000. I happen to know that the guy who held my new job last was paid $75,000 a year. How should I approach the president (my boss) to negotiate for more money? UNDERPAID

DEAR UNDERPAID: Very carefully. First of all, know that Sandra O'Neal, who runs Towers Perrin's compensation consulting practice in St. Louis, thinks you already blew it. "You should have raised the subject of money before you took on the new job, because now that you've accepted the position, you've lost your leverage," she says. "Before, your bargaining power would have been far greater." To try to regain that lost ground, be direct: Go to the president and simply point out that you're making a far greater contribution to the business now and you'd like to be rewarded accordingly. "In fact, any employee who can honestly make this case ought to be able to go and say this to his or her boss," says O'Neal. "I'd like to think we haven't sunk so low, or made things so needlessly complicated, that we can't just talk to each other like adults." It's a nice thought, anyway.

As for your predecessor's $75,000 salary, it ought to be regarded, for the purposes of this chat with your boss, as irrelevant. "I've seen people drive themselves nuts trying to peg their own pay to what somebody else in a similar job was or is making," says Peter LeBlanc, national director of Sibson & Co.'s performance and rewards practice. "And by the way, it's always someone whose pay is far higher that they're comparing themselves with. Nobody ever says, 'Gee, maybe what I'm doing isn't really worth that much money.'" LeBlanc points out that, with the advent of broadbanding, wide disparities in salary--for example, between $42,000 and $75,000--have become much more common: "Pay today isn't determined by job description or title but by experience, contribution, and special skills."

So don't march into the president's office, stamp your little foot, and demand $75,000. Instead, ask your boss to tell you in detail exactly what kind of performance he expects from you over the next six to 12 months and what specific results would be enough to put you in line for a big raise. Then do whatever it takes. "If you can go in there some months from now and say, 'I did this, this, and this,' then you are bargaining from a position of strength," says LeBlanc. "This is a matter of focusing on the reality that somehow people do eventually get paid what they are really worth. But saying, 'So-and-so got $75,000, so I want $75,000'--that's just whining." And whining will get you nowhere.

DEAR ANNIE: I work for someone who is always encouraging during our one-on-one sessions. Yet people tell me that, when my name is mentioned for bigger opportunities, he always says negative things to those who are interested in me. It's very confusing. How would you handle this? Should I confront him, or just go to work for someone else? CHUCK

DEAR CHUCK: You would be surprised--or then again, maybe you wouldn't--at how many people have asked me this same question lately. A wave of hypocrisy seems to be engulfing executive suites across the land, and it is interesting to speculate about why this might be. However, a direct confrontation, in which you essentially accuse your boss of disgraceful backstabbing behavior, is probably not a good idea.

Instead, ask for a thorough formal performance evaluation and get it in writing. That way, next time someone tells you he's been badmouthing you again, you can produce hard evidence that he's contradicting himself (if in fact he is). If that doesn't work, by all means find a new boss. Life is way too short for this kind of nonsense.

DEAR ANNIE: I'm interested in starting a 360-degree evaluation program in my company, with three evaluators for each employee--one at a level below, one at the same level, and one at a level above. I have some questions about this process. Where can I find detailed information about peer evaluations? RARING TO GO

DEAR RTG: An extremely useful guide to the practicalities--and pitfalls--of 360-degree evaluations is a new book by Mark R. Edwards and Ann J. Ewen called 360[degree] Feedback: The Powerful New Model for Employee Assessment & Performance Improvement (Amacom, $27.95). Edwards and Ewen are CEO and president, respectively, of a Tempe, Arizona, consulting outfit called Teams Inc. that developed the 360-degree systems now in use at IBM, GE, Disney, Intel, and Monsanto. Their very readable book is full of vivid case histories and other information that should help you get off to a good start.

One caveat: I spoke with Ann Ewen about your plan to have each employee evaluated by three other people. "You may want to consider adding more data points," she says. "We've found that, if just one colleague at each of three levels appraises someone, it opens the door to a person with a particular ax to grind--or for that matter a particular personal friendship--giving an evaluation that distorts the result." To get a more accurate reading, Ewen suggests a minimum of six to nine evaluators per employee.