Certainly not helicopters or tanks, both of which Leonardo had conceptualized in his time in the late 15th century. Although he had also invented in theory the calculator, he will probably be fascinated by a computer so powerful that it can process millions of calculations in the split of a second.

The existence of an underwater vessel that travels for years without refueling and carries weapons that can hit almost anywhere in the world, each capable of vaporizing a city instantly, would appeal to Leonardo the engineer and weapon-maker, but worry Leonardo the humanist.

He may even be slightly disappointed to find out that solar power is still far from being a main source of energy since he had invented centralized solar power 500 years ago.

Scientific progress in the last few centuries has been unprecedented in human history, yet given the explosion of innovations Leonardo had experienced in his lifetime alone, one has to doubt if any technological breakthrough can surprise the archetypal Renaissance man.

Now picture him walking into an office building. He sees hundreds of employees: engineers, managers, consultants, operators, human resource staff, electricians, technicians, plumbers, cooks, cleaners and some whose job titles have yet to be invented, all working in unison.

He would have been astonished by the sheer size of the manpower, amazed by the efficiency of these workers and by the science of management and business administration that are invented to enable such efficiency.

But the true shock will only register when he learns that it is not a government or a church office he is visiting. The hundreds of workers team up not to manage grandiose projects such as country-running, war waging or cathedral building. Such cooperation may produce only one single product.

He may find it wonderful, even spiritual, that these people dedicate a significant part of their lives to something much bigger than themselves.

An individual contributes only a little to the corporation's goal: The incessant search for perfection in research and development, manufacturing process, marketing and logistics, etc., to make better products more cheaply while selling them at higher prices.

Yet, minus the collective efforts of these people and the corporation collapses.Leonardo's final shock would take place when he talks with workers and finds out how little some think of their work. Some find their jobs mundane, some complain about the low pay, some harbor dreams of alternate careers as artists, fashion designers, movie stars, presidents or simply of making a lot of money.

There is something poetic about the modern middle-class working environment that has escaped the contemporary imagination. Ask any kid what his or her ideal occupation is, office job is seldom the answer.

Part of the reason is because the basic idea of jobs has not progressed much since Leonardo's time, when the middle-class did not even exist.

It is still the norm to define a job as a straight-forward occupation that makes things (inventors, artists), goes places (seafarers, astronauts), helps out (teachers, police officers, firemen) or being somebody (presidents, etc.) The middle-class, the pillar of modern society and democracy, is poorly represented in this field.

As the economic downturn brings back a sense of reality to the developed world and a better appreciation of jobs (anyone who still has a job now will look at it differently) to its workforce, now is the perfect time to reintroduce the virtue of middle-class work to society.

Reason, self-motivation, resilience and a composed personality are all great personal traits in any time.

They are now the basic attributes an office worker acquires on-the-job, but only after spending a substantial time working painfully under great pressure often without the benefit of a tangible fruit.

By advancing typical business training such as time management classes, enneagram tests, case studies, problem-solving analysis, etc., to earlier and more general education such as middle school or high school curriculum, students can be taught to manage their lives, optimize their time, find their working tempo and generally understand themselves better in terms of knowing how they operate early on.

It is laughable to suggest that general subjects such as history are not needed for students simply because not everyone needs it in her career.

It is equally naive to say that business knowledge is only for people in the business world.