Managers and leaders

Do the companies need managers or leaders? What are their functions?
One may say that both are needed. Quite right, but can we have two
people, one for management and one for leading? My reading of an
article in a HBR publication has given me a new revelation.

It says that manager's goals arise out of necessities, rather than
desires; and leaders are proactive in their approach. They set their
own targets, and work towards them. Managers, on the other hand, are
problem solvers. So both are needed, isn't it?

Leadership requires powers to influence the thoughts and actions of
other people. The risk of power games comes into the picture when
• There is a risk of equating power with the ability to get immediate results
• Risk of ignoring many different ways people can legitimately accumulate power
• Risk of losing self control in the desire for power

As a personality, manager emphasizes rationality, he is a problem
solver. Leadership is a kind of psychodrama in which the leader must
control himself before trying to control others.

In spite of being a 'born leader', there can be a great deal of
stagnation because of their limitations in visualizing purposes and
generating value at work.

Managers tend to adopt an impersonal attitude towards their goals.
These goals are created out of a need, and are more oriented towards
the organization, rather than the person. Leaders tend to get
passionate about their goals, and can have serious implications if
they fail to achieve those.

I don't feel like putting any more gyan, will do that sometime later.