The beginning and the end of an S-curve-the slow-moving parts of the curve-correspond to periods characterized by low rate of growth. In commerce such periods of stagnation represent bad business seasons, "winters". Death comes naturally in winter, but it does not have to be this winter. You can postpone death until next winter, or even the winter after next.

The development of a person's creativity and productivity is a natural growth process, and as such it is intimately related to S-curves. Obviously people's productivity increases and decreases with time. Youngsters cannot produce much because they have to learn first. Old people may become exhausted of ideas, energy, and motivation. It makes intuitive sense that productivity goes through a cycle over a person's lifetime, slowing down as it approaches the end. The cumulated productivity-the total number of works produced-will then look like an S-shaped curve over time.

In my book Predictions I discuss many well-documented artists and scientists demonstrating that the total number of creations in each case, graphed over time, trace rather complete S-curves over the lifetime of the person. When people die they generally find themselves in a low-growth period not far from the ceiling of their S-curve. I reproduce below the case of Mozart, which demonstrates well the phenomenon.

Counting every composition as one unit on the argument that a minuet at the age of six is no lesser a creative achievement than a requiem at the age of thirty-five, I found an S-curve that passes impressively close to all thirty-one yearly points representing the cumulative number of Mozart's compositions. There are two little irregularities, however; one on each end, see Exhibit 1.

The irregularity at the low end of the curve has to do with the fact that we get better agreement between the curve and the data if we assume that some twenty odd compositions are "missing" during Mozart's earliest years. His first recorded composition was created in 1762, when he was six. However, the S-curve's nominal beginning is around 1756, Mozart's birth date. Conclusion: Mozart was composing from the moment he was born. His first eighteen compositions, however, were never recorded due to "technical" reasons-the fact that he could neither write nor speak well enough to dictate them to his father.

The second irregularity is at the high end of the curve, the year of Mozart's death: 1791 shows a large increase in productivity. In fact, the data point falls well above the curve, corresponding more to the productivity projected for the year 1793. What was Mozart trying to do during the last year of his life? With his creative potential determined as 644 com-positions, his last composition would put him at the 91-percent level of exhaustion. Most people who die of old age have realized 90 percent of their creative potential. There was very little left for Mozart to do. His work in this world had been practically accomplished. The irregularity at the high end of his creativity curve indicated the sprint at the finish! What he had left to do was not enough to help him fight the illness that was consuming him. "Mozart died of old age" is the conclusion one would get by looking at Exhibit 1. Yet there is a popular belief that the world has been deprived of many musical masterpieces by his "premature" death.

In discussions with musicians, I have found that many are not shocked by the idea that Mozart may have exhausted his creative potential at the age of thirty-five. He had already contributed so much in every musical form of the time that he could no longer break new ground. Of course, he could have done more of the same: more concertos, more symphonies, more trios and quartets. But all this would have represented compromised innovation. He himself wrote at the age of twenty-one, "To live until one can no longer contribute anything new to music."

His Dissonant Quartet in C Major, K465 (1785) has been cited as evidence for Mozart's possible evolution, had he lived. I consider this an unlikely scenario. The learning curve of music lovers of that time could not accommodate the kind of music that became acceptable more than one hundred and fifty years later. Mozart would have soon stopped exploring musical directions that provoked public rejection.

Natural death does not necessarily come as a consequence of old age. Hemingway's suicide came at a time when his productivity S-curve had already flattened out-winter season-and from that point of view his suicide looks more like natural death. Even accidents may not really be true accidents when they occur in productivity's winter. They may be suicides in disguise. The absent-minded professor is less likely to be hit by a car crossing the street, if he or she is involved in an exciting research project.

But Mozart did not have to die at thirty-five just because he had exhausted the capability to further innovate in music. Cascading careers are known to exist and play a decisive role in long happy lives. Football players do not necessarily die upon retirement from the playing ground. Many retirees embark on new activities with success. Alfred Hitchcock followed such a course when he moved from cinema to television.

Exhibit 2 shows the number of films for which Hitchcock could claim credit at any time during his career. As a child Hitchcock manifested interest in theatrical plays, but as a teenager, he went to the cinema frequently and soon began visiting movie studios. At the age of twenty he took a modest job as a designer of titles for the silent movies of the time, pretending-something that he maintained even later-that he had no ambition to assume more responsibility. This is in contradiction to his insistence on learning everything there was to learn about filmmaking and volunteering to try out his hand at any new assignment. In fact, the lower part of the curve fitted to the data of his full-length films seems to originate well before 1925, when his first movie appeared. This means that his impulse for direction was deeply rooted. When he finally started his career as a film director at twenty-six, he produced prodigiously during the first six years, as if he were trying to "catch up," not unlike many others discussed in Predictions whose early careers display this sudden release of pent-up productivity.

From 1930 onwards the cumulative number of Hitchcock's full-length features grows smoothly to reach fifty-two by 1975. But the rate of growth is progressively lower after the mid-1950s. It is not by accident that in 1955 he was persuaded to make television films for the celebrated series Alfred Hitchcock Presents. The open circles on the graph represent the sum of both full-length plus the shorter television films. A shorter S-curve can be clearly outlined on top of the long one. This second niche contains twenty films; the process of filling it up starts in 1955, and flattens out approaching natural completion by 1962.

The evolution of Hitchcock's work just before he embarked on the television adventure contains a suggestive signal, a slowing-down that leads smoothly into the subsequent television activity. Statistically speaking, the small deviation of the data points around 1951 has no real significance. It coincides, however, with the period that the U.S. film industry felt most strongly the competition from the growing popularity of television. It also coincides with the time Hitchcock's main-feature career entered a period of declining growth heading for a winter. The television series provided Hitchcock with new potential for creativity and another high-growth period for his career. He was fortunate in his timing. New career cycles, like agricultural crops, must be seeded before the winter of the previous cycle really settles in.

There are many examples of individuals who had two and three or more cascading careers with an S-curve describing each one of them. Typically, women launch a new activity once the fertility curve ends in the early forties. Likewise, athletes and others with careers strongly dependent on physical condition embark on more intellectual pursuits (coaching, writing, and so on). Two conditions must be satisfied for a successful career renewal. One is timing-that is, the seeds must be put down before the winter season of the previous career. The other condition is that the new activity must be sufficiently differentiated so as to constitute a new "species". Mozart's timing was right. He composed the Dissonant Quartet-if we consider it for a moment as his attempt to branch out into a new niche for musical composition-as his career was heading for a winter. But the new "species" was neither differentiated enough nor gifted for survival (it was rejected as being too far ahead of its time.) Mozart would have had a better chance to secure a second lease on life as a musicologist, a music critique, or even a writer.

A Second Lease on Life does not concern only careers. Anything that grows in competition-products, technologies, means of transportation, energy sources, even the popularity of stocks at the stock market-will go through the phases beginning, growth, maturity, decline, and death. However, the time frames may be very different (e.g., oil as dominant energy source could be 50 years while a stock's popularity could last as little as a few weeks). In most cases a replacement will take over. If the replacement is different enough and comes at the right time (during the declining phase of the predecessor) it will have good chances of becoming successful.

It then becomes crucial to position yourself. Where are you on the curve? How far is winter? There are many ways to do this accurately (I have even developed software tools for that purpose). But there is a simple way based on the fact that the life-cycle curve-bell-shaped-is symmetric. Just try to feel if you have reached the peak of your productivity in whatever represents your life's activity. If you decide you are somewhere around your peak, comfort yourself with the idea that ahead of you lies a period comparable in length to the one you have had so far. If every year (or quarter, or month, whatever the time frame may be) the annual increase of your output is greater that what it was the previous year, you are still a "youngster", that is, you have not reached yet the mid-point of your curve. But if year-to-year growth in absolute terms is getting smaller every year, it is time you began thinking about a "replacement product."