Not all sounds made by animals serve as language, and we have only to turn to that extraordinary discovery of echolocation (回声定位) in bats to see a case in which the voice plays a strictly practical role. To get a full appreciation of what this means we must turn first to some recent human inventions. Everyone knows that if he shouts near a wall or a mountainside, an echo will come back. The further off this solid obstacle, the longer time it will take for the return of the echo. A sound made by tapping on the main body of a ship will be reflected from the sea bottom, and by measuring the time interval between the taps and the receipt of the echoes the depth of the sea at that point can be calculated. So was born the echo-sounding equipment, now in general use in ships. Every solid object will reflect a sound, varying according to the size and nature of the object. A shoal of fish will do this. So it is a comparatively simple step from locating the sea bottom to locating a shoal of fish. With experience, and with improved equipment, it is now possible not only to locate fish but to tell if it is herring, cod, or other well-known fish, by the pattern of its echo. A few years ago it was found that certain bats emit squeaks (吱吱声) and by receiving the echoes they could locate and steer clear of obstacles—or locate flying insects on which they feed. This echolocation in bats is often compared with radar, the principle of which is similar.

Real policemen hardly recognize any resemblance between their lives and what they see on TV—if they ever get home in time. There are similarities, of course, but the cops don't think much of them. The first difference is that a policeman's real life revolves round the law. Most of his training is in criminal law. He has to know exactly what actions are crimes and what evidence can be used to prove them in court. He has to know nearly as much law as a professional lawyer, and what is more, he has to apply it on his feet, in the dark and rain, running down an alley after someone he wants to talk to. Little of his time is spent in chatting to scantily-clad (衣着暴露的) ladies or in dramatic confrontations with desperate criminals. He will spend most of his working life typing millions of words on thousands of forms about hundreds of sad, unimportant people who are guilty—or not—of stupid, petty crimes. Most television crime drama is about finding the criminals: as soon as he's arrested, the story is over. In real life, finding criminals is seldom much of a problem. Except in very serious cases like murders and terrorist attack—where failure to produce results reflects on the standing of the police—little effort is spent on searching. Having made an arrest, a detective really starts to work. He has to prove his case in court and to do that he often has to gather a lot of different evidence. So, as well as being overworked, a detective has to be out at all hours of the day and night interviewing his witnesses and persuading them, usually against their own best interests, to help him.

In a moment of personal crisis, how much help can you expect from a New York taxi driver? I began studying this question and found the answers interesting. One morning I got into three different taxis and announced, "Well, it's my first day back in New York in seven years. I've been in prison." Not a single driver replied, so I tried again. "Yeah, I shot a man in Reno." I explained, hoping the driver would ask me why, but nobody asked. The only response came from a Ghanaian driver, "Reno? That is in Nevada?" Taxi drivers were uniformly sympathetic when I said I'd just been fired. "This is America," a Haitian driver said. "One door is closed. Another is open." He argued against my plan to burn down my boss's house. A Pakistani driver even turned down a chance to profit from my loss of hope; he refused to take me to the middle of the George Washington Bridge—a $20 trip. "Why you want to go there? Go home and relax. Don't worry. Take a new job." One very hot weekday in July, while wearing a red ski mask and holding a stuffed pillowcase with the word "BANK" on it, I tried calling a taxi five times outside different banks. The driver picked me up every time. My ride with a Haitian driver was typical of the superb assistance I received. "Let's go across the park." I said. "I just robbed the bank there. I got $25,000." "$25,000?" he asked. "Yeah, you think it was wrong to take it?" "No, man. I work 8 hours and I don't make almost $70. If I can do that, I do it too." As we approached 86th and Lexington, I pointed to the Chemical Bank. "Hey, there's another bank," I said, "Could you wait here a minute while I go inside?" "No, I can't wait. Pay me now." His reluctance may have had something to do with money—taxi drivers think the rate for waiting time is too low—but I think he wanted me to learn that even a bank robber can't expect unconditional support.

The publishing of management books is unceasing. But are they teaching us the right lessons? They promise to reveal the secrets of being a great change agent. Their prescriptions are usually pretty similar and seem sensible. They tell us successful managers set ambitious goals, build a sense of purpose, trust their people, invest in the future, and so on. They are also alike in tone, favoring the missionary, you-can-do-it style, pioneered by Dale Carnegie's How to Win Friends and Influence People. But if there is one cause of skepticism, it is how bad these books have been in their choice of examples. The most famous example of this was the Peters and Waterman book, In Search of Excellence, which triggered the current publishing boom. They carefully chose the 40 firms that had been the most outstanding performers in the past decade and from this sample identified 12 golden rules of management. Unfortunately, a decade later, two-thirds of these excellent companies had gone bankrupt or been taken over. It is a trap that all these books have fallen into. For decades Peter Drucker held up British retailer Marks & Spencer as the world's best managed company. Past books have admired the greatness of Saatchi & Saatchi, IBM, Hanson, GEC, or, until the recent crash in internet stocks, the virtues of Amazon, Priceline and Lastminute.com. Why is success so fast? Why do the books get it so wrong? One problem is that they all ignore luck. Over time, virtually all gamblers lose. However, once in a while, someone will still have an amazing streak (一连串) of luck. But studying how this gambler plans and thinks is completely purposeless—his run of luck is pure chance. So it is with many companies that have had a run of success. Often there is little to be learned, because as with M&S, their luck will run out tomorrow.

Faces, like fingerprints, are unique. Did you ever wonder how it is possible for us to recognize people? Even a skilled writer probably could not describe all the features that make one face different from another. Yet a very young child—or even an animal, such as a pigeon—can learn to recognize faces. We all take this ability for granted. We also tell people apart by how they behave. When we talk about someone's personality, we mean the ways in which he or she acts, speaks, thinks and feels that make that individual different from others. like the human face, human personality is very complex. But describing someone's personality in words is somewhat easier than describing his face. If you were asked to describe what a "nice face" looked like, you probably would have a difficult time doing so. But if you were asked to describe a "nice person," you might begin to think about someone who was kind, considerate, friendly, warm, and so forth. There are many words to describe how a person thinks, feels and acts. Gordon Allports, an American psychologist, found nearly 18,000 English words characterizing differences in people's behavior. And many of us use this information as a basis for describing, or typing, his personality. Bookworms, conservatives, military types—people are described with such terms. People have always tried to "type" each other. Actors in early Greek drama wore masks to show the audience whether they played the villain's (坏人) or the hero's role. In fact, the words "person" and "personality" come from the Latin persona, meaning "mask". Today, most television and movie actors do not wear masks. But we can easily tell the "good guys" from the "bad guys" because the two types differ in appearance as well as in actions.

More and more, the operations of our business, governments, and financial institutions are controlled by information that exists only inside computer memories. Anyone clever enough to modify this information for his own purposes can get substantial rewards. Even worse, a number of people who have done this and been caught at it have managed to get away without punishment. It's easy for computer crimes to go undetected if no one checks up on what the computer is doing. But even if the crime is detected, the criminal may walk away not only unpunished but with a glowing recommendation from his former employers. Of course, we have no statistics on crimes that go undetected. But it's disturbing to note how many of the crimes we do know about were detected by accident, not by systematic inspections or other security procedures. The computer criminals who have been caught may be the victims of uncommonly bad luck. For example, a certain keypunch (键盘打孔) operator complained of having to stay overtime to punch extra cards. Investigation revealed that the extra cards she was being asked to punch were for dishonest transactions. In another case, dissatisfied employees of the thief tipped off (向......透露) the company that was being robbed. Unlike other lawbreakers, who must leave the country, commit suicide, or go to jail, computer criminals sometimes escape punishment, demanding not only that they not be charged but that they be given good recommendations and perhaps other benefits. All too often, their demands have been met. Why? Because company executives are afraid of the bad publicity that would result if the public found out that their computer had been misused. They hesitate at the thought of a criminal boasting in open court of how he juggled (耍弄) the most confidential records right under the noses of the company's executives, accountants, and security staff. And so another computer criminal departs with just the recommendations he needs to continue his crimes elsewhere.