Almost finished reading Influence by Robert Cialdini. Most of it is stuff I learned in my social psych classes back in college, but having a refresher course didn't hurt. Originally, this book sold itself as a prophylactic measure - by reading this book, you'd be able to defend yourself against certain less-than-totally-honest sales tactics. But that's probably not the reason salespeople read it - and probably not the reason it was recommended on the "personal mba" book list - they read it because they want to know what those sales tactics are.
As a prophylactic, I think this material should be taught in elementary school. Suckers keep falling for these same tired old sales devices. Just as an obvious example, the "scarcity" principle - people are automatically suckered into buying things that they think are scarce. Witness the current Xbox 360 craze - where there was one reported fist-fight - this is a ploy by Microsoft, people! They purposely manufacture less than they think they'll sell, to create the same sort of buying hysteria you're being suckered into! And then they make sure to publicize plenty of press releases about their worries that there will be a shortage! So everyone lines up to buy the stupid thing, instead of actually waiting for, say, a good game for it! This has been a console manufacturer trick going back ages! And we keep falling for it!
Magic: The Gathering employs the technique as well, with their "rare" cards.
And then there's "low-balling" - this is making a ridiculous offer first, and then conceding to a more reasonable offer. "You don't want to buy our top of the line, zillion-dollar model? Well, all right, I suppose we could offer you this more modest product at this more reasonable price." This works on a couple of different levels: studies have shown you'll simply be more likely to buy if you're introduced to the offer in this way. And on another level, it's simply good negotiating, making you more likely to squeeze some of that "surplus value" out of your mark. And on another level, the mark is usually not aware it's happening to him, and often feels like he's taking advantage of you! "I talked him down to this!"
It does occasionally backfire - I talked to one guy who turned down a job at Treyarch specifically because our CTO "low-balled" him. "Will you do it for this much money?" the CTO asked. "No," he said. Later, he got a phone call. "How about this much?" And then, even though that amount was in the ballpark he was looking for, he refused to take the job on principle. This is one of the few things Treyarch used to do that I disagreed with on principle - but maybe I'll be singing a different tune when I run my own company - we paid our employees as little as we could get away with. On a spreadsheet it looks great - every dollar you're not paying an employee is a dollar of profit on the contract they're working on. And most of your employees, if they suddenly decide they're making too little money, will give you a chance to give them a raise before they jump ship. But every now and then it'll backfire, like the aforementioned guy. Also, you may end up with the guy who feels entitled to coast because at some level he knows or has heard he's not making what he should. But most importantly, I just don't like the idea of paying someone what they'll take rather than what they're worth.
Getting To Yes has a different take on how to negotiate salary. And, I'd say Getting To Yes and How To Win Friends And Influence People are both more important books because they're not about manipulation: the person you're selling to / negotiating with can have read the same book and it'll still help you close the deal or make the sale.
So, back to "teaching this stuff in elementary school" - imagine if we taught everyone how to recognize and resist these practices. Used car salesmen would no longer be able to high-ball. "I just talked to the boss and he said he won't go for that price." (A friend just got a game development contract renegotiated on him like this.) Microsoft and QVC would stop using their scarcity tactics. Salaries would be negotiated fairly. People wouldn't get conned into certain classes of scams. And so on.